Replace pip index versions with PyPI API check in release workflow

The pip index versions command fails consistently on Linux runners,
likely due to PEP 668 externally-managed Python on Ubuntu 24.04.
Use the PyPI JSON API via curl instead, which is more reliable.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: adamtheturtle

.github/workflows/release.yml

@@ -222,7 +222,7 @@ jobs:
           max_attempts: 50
           command: |
             normalized_version=$(echo "${{ needs.build.outputs.new_tag }}" | sed -E 's/\.0+([0-9])/.\1/g')
-            pip index versions vws-cli | grep -wq "$normalized_version"
+            curl -sf "https://pypi.org/pypi/vws-cli/${normalized_version}/json" > /dev/null
 
       - name: Create requirements file
         run: echo "vws-cli==${{ needs.build.outputs.new_tag }}" > requirements.txt
@@ -321,7 +321,7 @@ jobs:
           shell: bash
           command: |
             normalized_version=$(echo "${{ needs.build.outputs.new_tag }}" | sed -E 's/\.0+([0-9])/.\1/g')
-            pip index versions vws-cli | grep -wq "$normalized_version"
+            curl -sf "https://pypi.org/pypi/vws-cli/${normalized_version}/json" > /dev/null
 
       - name: Create requirements file
         run: echo "vws-cli==${{ needs.build.outputs.new_tag }}" > requirements.txt
@@ -381,7 +381,7 @@ jobs:
           max_attempts: 50
           command: |
             normalized_version=$(echo "${{ needs.build.outputs.new_tag }}" | sed -E 's/\.0+([0-9])/.\1/g')
-            pip index versions vws-cli | grep -wq "$normalized_version"
+            curl -sf "https://pypi.org/pypi/vws-cli/${normalized_version}/json" > /dev/null
 
       - name: Create requirements file
         run: echo "vws-cli==${{ needs.build.outputs.new_tag }}" > requirements.txt