chore: create .git-blame-ignore-revs (#2955)

Author: maelle

.Rbuildignore

@@ -26,3 +26,4 @@
 ^vignettes/articles$
 ^\.vscode$
 ^[\.]?air\.toml$
+^\.git-blame-ignore-revs$

.git-blame-ignore-revs

@@ -0,0 +1,8 @@
+# This file lists revisions of large-scale formatting/style changes so that
+# they can be excluded from git blame results.
+#
+# To set this file as the default ignore file for git blame, run:
+#   $ git config blame.ignoreRevsFile .git-blame-ignore-revs
+
+# https://github.com/r-lib/pkgdown/pull/2865
+3245437e22fb284f9e9fbbb62df5ef0ccba47715