chore(blog): add release notes for 2.5.0 release

pages/blog/release-notes-2.5.0.md

@@ -0,0 +1,94 @@
+---
+title: AsyncAPI Spec 2.5.0 Release Notes
+date: 2022-09-20T16:41:00+01:00
+type: Communication
+tags:
+  - Specification
+  - Release Notes
+cover: /img/posts/release-notes-2.5.0/cover.webp
+authors:
+  - name: Vladimír Gorej
+    photo: /img/avatars/char0n.webp
+    link: https://twitter.com/vladimirgorej
+    byline: Open Source Software Engineer, OSS contributor, author and content creator.
+excerpt: "AsyncAPI 2.5 is now released. This brings really helpful additions, such as extended Server Variables reusability, and many clarifications"
+featured: true
+---
+
+The new version of the AsyncAPI specification - 2.5.0 - is now available.
+
+> This is a minor release, and it doesn't bring any breaking changes. You can switch to it by modifying the following value in your AsyncAPI file `asyncapi: '2.4.0'` into `asyncapi: '2.5.0'`
+
+## Server Variables can be now referenced from inside the Server Object 
+
+Previous AsyncAPI 2.4.0 release came with support of [defining Server Variable Objects as reusable components](https://www.asyncapi.com/blog/release-notes-2.4.0#server-variables-can-be-now-referenced-from-components).
+Unfortunately AsyncAPI 2.4.0 doesn't allow to reference reusable server variable objects from within the `Server Object`.
+So we ended up in a situation that reusable server variable objects can be defined, but they actually cannot be reused.
+AsyncAPI 2.5.0 remedies this deficiency by allowing to use `Reference Object` whenever `Server Variable Object` can be used inside `Server.variables` field.
+
+Following example is now fully compliant with the specification:
+
+```yaml
+asyncapi: 2.4.0
+servers:
+  development:
+    $ref: '#/components/servers/myserver'
+  production:
+    $ref: '#/components/servers/myserver'
+components:
+  servers:
+    myserver:
+      url: "{stage}.my-server.com:{port}"
+      protocol: ws
+      variables:
+        stage:
+          $ref: "#/components/serverVariables/stage"
+        port:
+          $ref: "#/components/serverVariables/port"
+  serverVariables:
+    stage:
+      default: dev
+    port:
+      enum: [5000, 6000]
+      default: 5000
+```
+
+This new feature was contributed by [Vladimír Gorej](https://github.com/char0n). For more detail, see [Vladimír's `/spec #776` pull request](https://github.com/asyncapi/spec/pull/776) and the [GitHub issue where Vladimír's change to `serverVariables ` was discussed](https://github.com/asyncapi/spec/issues/775).
+
+## Decorating Server Object with tags
+
+placeholder for description
+
+## Clarifications
+
+Here are notable clarifications that got into AsyncAPI 2.5.0 release. Here is the list of notable clarifications that may have
+impact on the tooling authors:
+
+**ChannelItem.$ref resolution rules**
+
+All references of `MUST be in the format of a URL` sentence have been substituted with `This MUST be in the form of an absolute URL`.
+The meaning of `absolute URL` is now defined by [RFC3986, section 4.3](https://datatracker.ietf.org/doc/html/rfc3986#section-4.3).
+
+**Clarification around URL resolution rules**
+
+The resolution rules around `ChannelItem.$ref` field were not clearly defined. AsyncAPI 2.5.0 comes with explicit clarification
+that the resolution is done as defined by the [JSON Reference](https://tools.ietf.org/html/draft-pbryan-zyp-json-ref-03).
+
+## Tooling support
+
+The following official AsyncAPI tools are already updated to support 2.5.0 version of the specification:
+- JSON Schema that supports validation of AsyncAPI documents is updated in [this](https://github.com/asyncapi/spec-json-schemas) repository. Also **@asyncapi/specs** package has been updated on NPM to version `<version>`, and it contains the 2.4.0 JSON Schema.
+- [JavaScript Parser](https://github.com/asyncapi/parser-js/) uses latest **@asyncapi/specs** package and can be used to parse and validate 2.5.0 documents. Upgrade to `<version>` version.
+- [HTML template](https://github.com/asyncapi/html-template) uses the latest **@asyncapi/react-component** package. Upgrade to `<version>` version.
+- [JavaScript Converter](https://github.com/asyncapi/converter-js/) enables conversion from any AsyncAPI version into the 2.5.0 version of the spec. Upgrade to `<version>` version.
+- [Generator](https://github.com/asyncapi/generator/) uses the latest @asyncapi/parser package, so while generating output, it can validate 2.5.0 documents. Upgrade to `<version>` version.
+
+Last but not least is the AsyncAPI Studio. [Check out the Studio with this example](https://studio.asyncapi.com/?url=https://raw.githubusercontent.com/asyncapi/spec/v2.5.0/examples/websocket-gemini.yml).
+
+## Look ahead
+
+We aim to have a regular cadence of releases of the AsyncAPI specification, four times a year. For more information about when to expect future releases, you can see our [release process document](https://github.com/asyncapi/spec/blob/master/RELEASE_PROCESS.md#release-cadence).
+
+We're also working on the next major release of the AsyncAPI specification: 3.0.0. If you'd like to contribute, or just follow the discussions, you can see [Work on 3.0 release issue](https://github.com/asyncapi/spec/issues/691).
+
+> Photo by <a href="https://unsplash.com/@jeremythomasphoto?utm_source=unsplash&utm_medium=referral&utm_content=creditCopyText">Jeremy Thomas</a> on <a href="https://unsplash.com/?utm_source=unsplash&utm_medium=referral&utm_content=creditCopyText">Unsplash</a>