chore(deps): update actions/setup-python action to v6.3.0 #3381

Job	Run time
Integration Tests (pdm.lock)	23s
Integration Tests (pdm.minimal.lock)	21s
test_min_deps (ubuntu-latest)	36s
test_min_deps (macos-latest)	28s
test (3.11, ubuntu-latest)	45s
test (3.12, macos-latest)	59s
test_min_deps (windows-latest)	1m 46s
test (3.13, ubuntu-latest)	58s
test (3.13, macos-latest)	1m 22s
test (3.11, windows-latest)	1m 37s
test (3.12, windows-latest)	1m 33s
test (3.13, windows-latest)	1m 45s
test (3.12, ubuntu-latest)	58s
test (3.11, macos-latest)	41s
test (3.14, ubuntu-latest)	48s
test (3.14, windows-latest)	1m 27s
test (3.14, macos-latest)	50s
Combine & check coverage	15s
	17m 32s

Provide feedback