ci: publish snapshots to correct builds repository branch

With 1d67721, the snapshots CI job
was migrated from CircleCI to GitHub actions, but the underlying scripts
were not updated to no longer depend on CircleCI specifics.

scripts/deploy/publish-build-artifacts.sh

@@ -40,7 +40,7 @@ publishPackage() {
 
   buildDir="$(pwd)/dist/releases/${packageName}"
   buildVersion=$(node -pe "require('./package.json').version")
-  branchName=${CIRCLE_BRANCH:-'main'}
+  branchName=${GITHUB_REF_NAME:-'main'}
 
   commitSha=$(git rev-parse --short HEAD)
   commitAuthorName=$(git --no-pager show -s --format='%an' HEAD)

scripts/deploy/publish-docs-content.sh

@@ -34,7 +34,7 @@ docsContentRepoUrl="https://github.com/angular/material2-docs-content"
 buildVersion=$(node -pe "require('./package.json').version")
 
 # Name of the branch that is currently being deployed.
-branchName=${CIRCLE_BRANCH:-'main'}
+branchName=${GITHUB_REF_NAME:-'main'}
 
 # Additional information about the last commit for docs-content commits.
 commitSha=$(git rev-parse --short HEAD)