ci: Remove usage of macos-11 (#681)

* ci: Remove usage of macos-11

This is being removed at GitHub on June 28, 2024.

Switch semver action to macos-14.

* Use `macos-14` instead of `macos-14.0` for semver check

---------

Co-authored-by: Martin Robinson <mrobinson@igalia.com>

.github/workflows/rust.yml

@@ -22,7 +22,7 @@ jobs:
           components: rustfmt
       - run: cargo fmt --check
   semver:
-    runs-on: macos-11.0
+    runs-on: macos-14
     steps:
     - uses: actions/checkout@v4
     - name: Check semver
@@ -31,7 +31,7 @@ jobs:
     runs-on: ${{ matrix.os }}
     strategy:
       matrix:
-        os: [macos-11.0, macos-12, macos-13, macos-14]
+        os: [macos-12, macos-13, macos-14]
         toolchain: [stable]
         include:
           - os: macos-14