Remove hardcoded versions from workflows. (#16540)

This PR removes hardcoded Python versions from CI workflows. It is a prerequisite for dropping Python 3.9. See rapidsai/build-planning#88.

Authors:
  - Bradley Dice (https://github.com/bdice)

Approvers:
  - James Lamb (https://github.com/jameslamb)

URL: #16540

.github/workflows/pandas-tests.yaml

@@ -19,7 +19,8 @@ jobs:
       secrets: inherit
       uses: rapidsai/shared-workflows/.github/workflows/[email protected]
       with:
-        matrix_filter: map(select(.ARCH == "amd64" and .PY_VER == "3.9" and (.CUDA_VER | startswith("12.5.")) ))
+        # This selects "ARCH=amd64 + the latest supported Python + CUDA".
+        matrix_filter: map(select(.ARCH == "amd64")) | group_by(.CUDA_VER|split(".")|map(tonumber)|.[0]) | map(max_by([(.PY_VER|split(".")|map(tonumber)), (.CUDA_VER|split(".")|map(tonumber))]))
         build_type: nightly
         branch: ${{ inputs.branch }}
         date: ${{ inputs.date }}

.github/workflows/pr.yaml

@@ -187,6 +187,7 @@ jobs:
     secrets: inherit
     uses: rapidsai/shared-workflows/.github/workflows/[email protected]
     with:
+      # This selects "ARCH=amd64 + the latest supported Python + CUDA".
       matrix_filter: map(select(.ARCH == "amd64")) | group_by(.CUDA_VER|split(".")|map(tonumber)|.[0]) | map(max_by([(.PY_VER|split(".")|map(tonumber)), (.CUDA_VER|split(".")|map(tonumber))]))
       build_type: pull-request
       script: ci/cudf_pandas_scripts/run_tests.sh
@@ -196,7 +197,8 @@ jobs:
     secrets: inherit
     uses: rapidsai/shared-workflows/.github/workflows/[email protected]
     with:
-      matrix_filter: map(select(.ARCH == "amd64" and .PY_VER == "3.9" and (.CUDA_VER | startswith("12.5.")) ))
+      # This selects "ARCH=amd64 + the latest supported Python + CUDA".
+      matrix_filter: map(select(.ARCH == "amd64")) | group_by(.CUDA_VER|split(".")|map(tonumber)|.[0]) | map(max_by([(.PY_VER|split(".")|map(tonumber)), (.CUDA_VER|split(".")|map(tonumber))]))
       build_type: pull-request
       script: ci/cudf_pandas_scripts/pandas-tests/run.sh pr
       # Hide test failures because they exceed the GITHUB_STEP_SUMMARY output limit.