Update Germany holidays: add East German Uprising Day 2028 in Berlin … #5038

Job	Run time
Run pre-commit	32s
CodeQL	1m 40s
Test Python 3.9 on macos-latest	57s
Test Python 3.10 on macos-latest	50s
Test Python 3.11 on macos-latest	44s
Test Python 3.12 on macos-latest	54s
Test Python 3.13 on macos-latest	38s
Test Python 3.9 on ubuntu-latest	56s
Test Python 3.10 on ubuntu-latest	1m 1s
Test Python 3.11 on ubuntu-latest	53s
Test Python 3.12 on ubuntu-latest	1m 22s
Test Python 3.13 on ubuntu-latest	1m 16s
Test Python 3.9 on windows-latest	1m 42s
Test Python 3.10 on windows-latest	1m 53s
Test Python 3.11 on windows-latest	2m 0s
Test Python 3.12 on windows-latest	2m 11s
Test Python 3.13 on windows-latest	2m 22s
Build distribution	36s
Test docs build	37s
Test build on macos-latest	27s
Test build on ubuntu-latest	44s
Test build on windows-latest	1m 53s
Publish generated artifacts	0s
	26m 8s

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