Pin @typescript-eslint dependencies

Prevent dependabot from attempting to upgrade
`@typescript-eslint/eslint-plugin` and `@typescript-eslint/parser` to
v8, because `eslint-config-airbnb-typescript` still depends on v7.

Issue PhilanthropyDataCommons/meta#153

.github/dependabot.yml

@@ -12,6 +12,10 @@ updates:
         update-types: ['version-update:semver-major']
       - dependency-name: 'eslint'
         update-types: ['version-update:semver-major']
+      - dependency-name: '@typescript-eslint/eslint-plugin'
+        update-types: ['version-update:semver-major']
+      - dependency-name: '@typescript-eslint/parser'
+        update-types: ['version-update:semver-major']
     groups:
       aws-sdk:
         patterns: