Rename repo to vgi-easter-python; fix CI concurrency collision #13

Job	Run time
unit (ubuntu-latest)	13s
unit (windows-latest)	33s
unit (macos-latest)	10s
resolve-haybarn	2s
integration (windows-latest, haybarn_unittest-windows-amd64.zip)	35s
integration (macos-latest, haybarn_unittest-osx-arm64.zip)	17s
integration (ubuntu-latest, haybarn_unittest-linux-amd64.zip)	14s
	2m 4s

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