ci/docs: Update the list of supported releases

Author: bilelmoussaoui

.github/workflows/docs.yml

@@ -38,13 +38,10 @@ jobs:
       image: ghcr.io/gtk-rs/gtk4-rs/gtk4:latest
     env:
       RELEASES: |
+        0.10=0.10
         0.9=0.9
         0.8=0.8
         0.7=0.7
-        0.6=0.6
-        0.5=0.5
-        0.4=0.4
-        0.3=0.3
       RUSTFLAGS: --cfg docsrs
     steps:
       - uses: actions/checkout@v4