dependabot npm(deps): bump log4js from 6.8.0 to 6.9.1

Bumps log4js from 6.8.0 to 6.9.1.

Changelog

Sourced from log4js's changelog.

6.9.1

• fix(7922e82): regex for stacktrace - thanks @​lamweili
  • addresses #1377 which has a regression since 6.8.0 from #1363 at commit 7922e82

6.9.0

• feat: support for idempotent logging on browser - thanks @​aellerton
  • addresses #968, #1270, #1288, #1372
• docs: added that log4js.getLogger() may call log4js.configure() - thanks @​lamweili

Commits

• 26dcec6 6.9.1
• 63ae5b9 Merge pull request #1379 from log4js-node/update-docs
• 185fa66 docs: updated changelog for 6.9.1
• ed54dc2 Merge pull request #1378 from log4js-node/1377-defaultparsecallstack-cant-par...
• 2628688 fix(7922e82): regex for stacktrace
• b3919d8 6.9.0
• 7cfe8a4 Merge pull request #1376 from log4js-node/update-docs
• f89e7b6 docs: updated changelog for 6.9.0
• 0082928 Merge pull request #1375 from log4js-node/update-docs
• c0db6a4 docs: added that log4js.getLogger() may call log4js.configure()
• Additional commits viewable in compare view