R_2_4_7
Sebastian Pipping
Sync years in file headers
Changes: Document #581
Fix typos and add ICPSR full name
.gitignore: Add missing
Extend .mailmap
Actions: Upgrade Clang from 11 to 13
Actions: Split off Cppcheck to stop installing 13 unrelated Homebrew formulas
Increase precision in existing MIT headers based on Git history