chore: Update README.md (google#7404)

Remove out of date info from readme.

README.md

@@ -42,7 +42,7 @@ Want to make Blockly better? We welcome contributions to Blockly in the form of
 
 ## Releases
 
-We release by pushing the latest code to the master branch, followed by updating the npm package, our [docs](https://developers.google.com/blockly), and [demo pages](https://google.github.io/blockly-samples/). We typically release a new version of Blockly once a quarter (every 3 months). If there are breaking bugs, such as a crash when performing a standard action or a rendering issue that makes Blockly unusable, we will cherry-pick fixes to master between releases to fix them. The [releases page](https://github.com/google/blockly/releases) has a list of all releases.
+We release by pushing the latest code to the master branch, followed by updating the npm package, our [docs](https://developers.google.com/blockly), and [demo pages](https://google.github.io/blockly-samples/). If there are breaking bugs, such as a crash when performing a standard action or a rendering issue that makes Blockly unusable, we will cherry-pick fixes to master between releases to fix them. The [releases page](https://github.com/google/blockly/releases) has a list of all releases.
 
 We use [semantic versioning](https://semver.org/). Releases that have breaking changes or are otherwise not backwards compatible will have a new major version. Patch versions are reserved for bug-fix patches between scheduled releases.
 
@@ -72,15 +72,7 @@ Unreleased APIs may change radically. Anything that is in `develop` but not `mas
 
 ## Issues and Milestones
 
-We typically triage all bugs within 2 working days, which includes adding any appropriate labels and assigning it to a milestone. Please keep in mind, we are a small team so even feature requests that everyone agrees on may not be prioritized.
-
-### Milestones
-
-**Upcoming release** - The upcoming release milestone is for all bugs we plan on fixing before the next release. This typically has the form of `year_quarter_release` (such as `2019_q2_release`). Some bugs will be added to this release when they are triaged, others may be added closer to a release.
-
-**Bug Bash Backlog** - These are bugs that we're still prioritizing. They haven't been added to a specific release yet, but we'll consider them for each release depending on relative priority and available time.
-
-**Icebox** - These are bugs that we do not intend to spend time on. They are either too much work or minor enough that we don't expect them to ever take priority. We are still happy to accept pull requests for these bugs.
+We typically triage all bugs within 1 week, which includes adding any appropriate labels and assigning it to a milestone. Please keep in mind, we are a small team so even feature requests that everyone agrees on may not be prioritized.
 
 ## Good to Know