Have dependabot ignore eslint-plugin-mocha (#1888)

Author: award999

.github/dependabot.yml

@@ -22,6 +22,8 @@ updates:
       - dependency-name: "@types/svgicons2svgfont"
       - dependency-name: "octokit"
         update-types: ["version-update:semver-major"]
+      - dependency-name: "eslint-plugin-mocha"
+        update-types: ["version-update:semver-major"]
       # Newer versions of fantasticon are broken on Windows.
       # https://github.com/tancredi/fantasticon/issues/470
       - dependency-name: "fantasticon"