Skip Snyk action for Dependabot PRs

The Snyk action fails because Dependabot cannot access the SNYK_TOKEN
secret.

Fix error during tests workflow:
`snyk` requires an authenticated account. Please run `snyk auth` and try
again.

Author: wimpyprogrammer

.github/workflows/tests.yml

@@ -43,6 +43,7 @@ jobs:
           fail_ci_if_error: true
 
       - name: Run Snyk to check for vulnerabilities
+        if: ${{ github.actor != 'dependabot[bot]' }}
         uses: snyk/actions/node@master
         env:
           SNYK_TOKEN: ${{ secrets.SNYK_TOKEN }}