fix: use atomic counter in pet-pipenv test temp dirs to prevent parallel collisions #1389

Job	Run time
Builds (ubuntu-latest, x86_64-unknown-linux-musl, yes)	2m 17s
Tests (ubuntu-latest, x86_64-unknown-linux-musl, yes)	9m 35s
Tests (macos-14, aarch64-apple-darwin, yes)	10m 9s
Builds (macos-latest, x86_64-apple-darwin, yes)	3m 8s
Tests in Containers (ci-jupyter-container, ubuntu-latest, mcr.microsoft.com/devcontainers/univers...	4m 53s
Builds (windows-latest, aarch64-pc-windows-msvc)	4m 34s
Tests (macos-latest, x86_64-apple-darwin, yes)	16m 21s
Env Tests (ci-poetry-global, windows-latest, x86_64-pc-windows-msvc)	6m 35s
Builds (macos-14, aarch64-apple-darwin, yes)	2m 5s
Env Tests (ci-poetry-custom, ubuntu-latest, x86_64-unknown-linux-musl)	3m 9s
Env Tests (ci-poetry-custom, windows-latest, x86_64-pc-windows-msvc)	5m 58s
Env Tests (ci-poetry-global, ubuntu-latest, x86_64-unknown-linux-musl)	2m 51s
Tests in Containers (ci-homebrew-container, ubuntu-latest, homebrew/brew, x86_64-unknown-linux-musl)	3m 54s
Builds (windows-latest, x86_64-pc-windows-msvc)	5m 43s
Env Tests (ci-poetry-project, windows-latest, x86_64-pc-windows-msvc)	5m 52s
Env Tests (ci-poetry-project, ubuntu-latest, x86_64-unknown-linux-musl)	2m 47s
Tests (windows-latest, x86_64-pc-windows-msvc, yes)	7m 26s
	1h 37m 17s

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