Dart SDK 1.20 no longer creates `packages` directories. Added comments to `pub` files section to differentiate what is needed for >= SDK 1.20 and what is additionally needed for older SDK versions.
# See https://www.dartlang.org/tools/private-files.html
# Files and directories created by pub
-.buildlog
+
+# SDK 1.20 and later (no longer creates packages directories)
.packages
-.project
.pub/
build/
+
+# Older SDK versions
+# (Include if the minimum SDK version specified in pubsepc.yaml is earlier than 1.20)
+.project
+.buildlog
**/packages/
+
# Files created by dart2js
# (Most Dart developers will use pub build to compile Dart, use/modify these
# rules if you intend to use dart2js directly