Merge #823: gui: bump rust version

3196a80 gui: bump liana:master and async-hwi:master (edouardparis)
99bc44d gui: remove base64 dep (edouardparis)
c9bb7b0 ci gui: rust version 1.74 for linter, 1.65 for tests (edouardparis)
1526d15 fix clippy errors for rust 1.74 (edouardparis)

Pull request description:

ACKs for top commit:
  edouardparis:
    Self-ACK 3196a80

Tree-SHA512: 21bf7e968d0b593788fac4c1a1f577763f541986c9dddc0c99ccef031277d059a77d5d74a7a183b7a42b8c015837e03264c3fb8f9f196d170aca3f85d527f49f

.github/workflows/main.yml

@@ -51,7 +51,7 @@ jobs:
       - uses: actions/checkout@v1
       - uses: actions-rs/toolchain@v1
         with:
-            toolchain: 1.65.0
+            toolchain: 1.75.0
             components: rustfmt, clippy
             override: true
       - name: rustfmt
@@ -68,7 +68,7 @@ jobs:
     strategy:
       matrix:
         toolchain:
-          - 1.65
+          - 1.65.0
           - nightly
         os:
           - ubuntu-latest