🚸 use GitHub token by default (#61)

This PR adjusts the action so that it is no longer necessary to
explicitly specify the GitHub token to circumvent the API rate limit.
To this end, it simply passes the repository's GitHub token (available
via `${{ github.token }}`) as a default for the `github_token` action
input.

This is similar to how this is handled in, e.g.,
https://github.com/peter-evans/create-pull-request; specifically
[here](5354f85616/action.yml (L4-L6)).

.github/workflows/test-windows.yml

@@ -23,7 +23,5 @@ jobs:
           }
       - name: Setup uv
         uses: ./
-        with:
-          github-token: ${{ secrets.GITHUB_TOKEN }}
       - run: uv sync
         working-directory: __tests__\fixtures\uv-project

.github/workflows/test.yml

@@ -30,8 +30,6 @@ jobs:
       - uses: actions/checkout@v4
       - name: Install default version
         uses: ./
-        with:
-          github-token: ${{ secrets.GITHUB_TOKEN }}
       - run: uv sync
         working-directory: __tests__/fixtures/uv-project
   test-specific-version:
@@ -46,7 +44,6 @@ jobs:
         uses: ./
         with:
           version: ${{ matrix.uv-version }}
-          github-token: ${{ secrets.GITHUB_TOKEN }}
       - run: uv sync
         working-directory: __tests__/fixtures/uv-project
   test-checksum:
@@ -69,13 +66,14 @@ jobs:
         with:
           version: "0.3.2"
           checksum: ${{ matrix.checksum }}
-          github-token: ${{ secrets.GITHUB_TOKEN }}
-  test-without-github-token:
+  test-with-explicit-token:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
       - name: Install default version
         uses: ./
+        with:
+          github-token: ${{ secrets.GITHUB_TOKEN }}
       - run: uv sync
         working-directory: __tests__/fixtures/uv-project
   test-uvx: