ci: unpin pypy-3.11 version in CI

Remove temporary pypy-3.11-v7.3.21 pins that were added pending
investigation of issue #6049. Use unversioned pypy-3.11 to allow
setup-python to resolve the latest available version.

Assisted-by: OpenCode:glm-5

Author: henryiii

.github/workflows/ci.yml

@@ -48,8 +48,7 @@ jobs:
             python-version: '3.14t'
             cmake-args: -DCMAKE_CXX_STANDARD=17 -DPYBIND11_TEST_SMART_HOLDER=ON
           - runs-on: ubuntu-latest
-            # Temporarily pinned pending investigation in issue #6049.
-            python-version: 'pypy-3.11-v7.3.21'
+            python-version: 'pypy-3.11'
             cmake-args: -DCMAKE_CXX_STANDARD=17
           - runs-on: ubuntu-latest
             python-version: 'graalpy-24.2'
@@ -119,8 +118,7 @@ jobs:
             python-version: 'pypy-3.10'
             cmake-args: -DCMAKE_CXX_STANDARD=17
           - runs-on: macos-latest
-            # Temporarily pinned pending investigation in issue #6049.
-            python-version: 'pypy-3.11-v7.3.21'
+            python-version: 'pypy-3.11'
           - runs-on: macos-latest
             python-version: 'graalpy-24.2'
 
@@ -153,8 +151,7 @@ jobs:
             python-version: 'pypy-3.10'
             cmake-args: -DCMAKE_CXX_STANDARD=17
           - runs-on: windows-latest
-            # Temporarily pinned pending investigation in issue #6049.
-            python-version: 'pypy3.11-v7.3.21'
+            python-version: 'pypy-3.11'
             cmake-args: -DCMAKE_CXX_STANDARD=20
           # The setup-python action currently doesn't have graalpy for windows
           # See https://github.com/actions/setup-python/pull/880