chore: pass npmClient config to semantic-release via environment variable (#84)

Uses NPM_CONFIG_NPMCLIENT=pnpm environment variable to ensure
semantic-release uses pnpm instead of npm when running npm version
commands. This fixes the EUNSUPPORTEDPROTOCOL error caused by
pnpm workspace: protocol in dependencies.

Author: mroderick

.github/workflows/release.yml

@@ -39,6 +39,6 @@ jobs:
         env:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
       - name: Release
-        run: pnpm exec multi-semantic-release
+        run: NPM_CONFIG_NPMCLIENT=pnpm pnpm exec multi-semantic-release
         env:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}