Run Gitea workflows on Ubuntu only

.gitea/workflows/jpeg2000.yml

@@ -23,31 +23,3 @@ jobs:
         run: |
           cargo test -p libremetaverse-imaging --features jpeg2000
           cargo check -p libremetaverse --features jpeg2000
-
-  macos:
-    runs-on: macos-latest
-    steps:
-      - uses: actions/checkout@v4
-      - uses: dtolnay/rust-toolchain@stable
-      - name: Install OpenJPEG
-        run: brew install openjpeg pkg-config
-      - name: Build and test optional feature
-        run: |
-          cargo test -p libremetaverse-imaging --features jpeg2000
-          cargo check -p libremetaverse --features jpeg2000
-
-  windows:
-    runs-on: windows-latest
-    env:
-      VCPKGRS_DYNAMIC: "1"
-    steps:
-      - uses: actions/checkout@v4
-      - uses: dtolnay/rust-toolchain@stable
-      - name: Install OpenJPEG
-        shell: pwsh
-        run: vcpkg install openjpeg:x64-windows
-      - name: Build and test optional feature
-        shell: pwsh
-        run: |
-          cargo test -p libremetaverse-imaging --features jpeg2000
-          cargo check -p libremetaverse --features jpeg2000