Release 0.4.1

What's Changed

• Backport PR #1256 on branch 0.4.x (Correct "strip_source" in README to "strip_sources") by @meeseeksmachine in #1257
• 0.4.x: Deprecate "classic" template for removal in 1.0.0 by @martinRenou in #1263
• Backport PR #1281 on branch 0.4.x (Fix existing CI) by @meeseeksmachine in #1339
• Backport PR #1300 on branch 0.4.x (Pin yarn to fix tests) by @meeseeksmachine in #1340
• Backport PR #1334 on branch 0.4.x (Do not clean up resources after execution) by @meeseeksmachine in #1335

Full Changelog: v0.4.0...v0.4.1