Auto merge of #542 - sagudev:patch-1, r=jdm

Update rust.yml

While preparing GitHub actions for surfman I found out that those commas should not be here. So now we installed beta toolchains but did build on stable.

Author: bors-servo

.github/workflows/rust.yml

@@ -40,8 +40,8 @@ jobs:
       with:
           profile: minimal
           toolchain: ${{ matrix.rust }}
-          override: true,
-          default: true,
+          override: true
+          default: true
     - name: ccache cache files
       if: startsWith(matrix.os, 'windows') != true
       uses: actions/[email protected]