Setup remote cache after auth success (#932)

It seems like there is some eagerness with GitHub actiosn starting to
run steps after a previous step is not totally complete or some issue
with ensuring those env variables are set correctlly across steps. This
forces us to wait until after we've successfully assumed the credentials
role to configure the cache.

Author: brianmichel

.github/actions/setup-sccache/action.yml

@@ -52,14 +52,21 @@ runs:
         }
 
     - name: Authenticate to AWS
+      id: aws-credentials
       uses: aws-actions/configure-aws-credentials@v3
       if: inputs.aws-arn != ''
       with:
         role-to-assume: ${{ inputs.aws-arn }}
         role-session-name: ToolchainCISccacheAccess
         aws-region: ${{ inputs.aws-region }}
 
-    - name: Setup sccache
+    - name: Setup sccache (remote)
+      if: inputs.aws-arn != '' && steps.aws-credentials.outcome == 'success'
+      uses: hendrikmuhs/ccache-action@a1209f81afb8c005c13b4296c32e363431bffea5 # v1.2.17
+      with:
+        variant: sccache
+
+    - name: Setup sccache (local)
       uses: hendrikmuhs/ccache-action@a1209f81afb8c005c13b4296c32e363431bffea5 # v1.2.17
       with:
         max-size: ${{ inputs.disk-max-size }}