chore: group @type definition updates with counterparts

They're currently grouped with all other dev dependency updates but this
will lead them to going out of sync with the packages they define types
for. If we don't bucket them in the development-dependencies group then
Dependabot should fall back to its default behaviour of grouping them
with their counterpart packages.

Author: ivomurrell

.github/dependabot.yml

@@ -16,6 +16,8 @@ updates:
           - 'patch'
       development-dependencies:
         dependency-type: 'development'
+        exclude-patterns:
+          - '@types/*'
         update-types:
           - 'minor'
           - 'patch'