Update Rust version in Dockerfile

Updated Rust from v1.60 to v1.61 for building the images.
Also made the rust version fixed for the Alpine build images to prevent
those images being build with a newer version when released.

.github/workflows/build.yml

@@ -140,7 +140,7 @@ jobs:
 
       # Upload artifact to Github Actions
       - name: Upload artifact
-        uses: actions/upload-artifact@6673cd052c4cd6fcf4b4e6e60ea986c889389535 # v3.0.0
+        uses: actions/upload-artifact@3cea5372237819ed00197afe530f5a7ea3e805c8 # v3.1.0
         with:
           name: vaultwarden-${{ matrix.target-triple }}${{ matrix.ext }}
           path: target/${{ matrix.target-triple }}/release/vaultwarden${{ matrix.ext }}