Fix shellcheck issues in doc-tests.yaml script

- Add `exit` commands for failed `cd`s
- Don't read from and write to `package.json` in the same pipeline
- Add double quotes around variables

.github/workflows/doc-tests.yaml

@@ -96,14 +96,15 @@ jobs:
         run: |
           echo "" > .gitmodules
           rm -rf content/*
-          cd content
+          cd content || exit 1
           # Rather than using a submodule, copy the teleport source into the
           # content directory.
-          cp -r $GITHUB_WORKSPACE/teleport $GITHUB_WORKSPACE/docs/content/current
-          cd $GITHUB_WORKSPACE/docs
-          jq -nr --arg version $BRANCH '{"versions": [{"name": $version,"branch": $version, "deprecated": false, "latest": true, "current": true }]}' > config.json
-          cat <<< "$(jq '.scripts."git-update" = "echo Skipping submodule update"' package.json)" > package.json
-          cat <<< "$(jq '.scripts."prepare-sanity-data" = "echo Using pre-populated Sanity data"' package.json)" > package.json
+          cp -r "$GITHUB_WORKSPACE/teleport" "$GITHUB_WORKSPACE/docs/content/current"
+          cd "$GITHUB_WORKSPACE/docs" || exit 1
+          jq -nr --arg version "$BRANCH" '{"versions": [{"name": $version,"branch": $version, "deprecated": false, "latest": true, "current": true }]}' > config.json
+          NEW_PACKAGE_JSON=$(jq '.scripts."git-update" = "echo Skipping submodule update"' package.json);
+          NEW_PACKAGE_JSON=$(jq '.scripts."prepare-sanity-data" = "echo Using pre-populated Sanity data"' <<< "$NEW_PACKAGE_JSON");
+          echo "$NEW_PACKAGE_JSON" > package.json;
           echo "{}" > data/events.json
           echo '{"bannerButtons":{"second":{"title":"LOG IN","url":"https://teleport.sh"},"first":{"title":"Support","url":"https://goteleport.com/support/"}},"navbarData":{"rightSide":{},"logo":"/favicon.svg","menu":[]}}' > data/navbar.json