Bump js-yaml from 3.12.0 to 3.13.1 in /plugins/git-sync

Bumps [js-yaml](https://github.com/nodeca/js-yaml) from 3.12.0 to 3.13.1.
- [Release notes](https://github.com/nodeca/js-yaml/releases)
- [Changelog](https://github.com/nodeca/js-yaml/blob/master/CHANGELOG.md)
- [Commits](nodeca/js-yaml@3.12.0...3.13.1)

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

plugins/git-sync/yarn.lock

@@ -292,8 +292,8 @@ are-we-there-yet@~1.1.2:
     readable-stream "^2.0.0 || ^1.1.13"
 
 argparse@^1.0.7:
-  version "1.0.9"
-  resolved "https://registry.yarnpkg.com/argparse/-/argparse-1.0.9.tgz#73d83bc263f86e97f8cc4f6bae1b0e90a7d22c86"
+  version "1.0.10"
+  resolved "https://registry.yarnpkg.com/argparse/-/argparse-1.0.10.tgz#bcd6791ea5ae09725e17e5ad988134cd40b3d911"
   dependencies:
     sprintf-js "~1.0.2"
 
@@ -2341,8 +2341,8 @@ js-tokens@^3.0.2:
   resolved "https://registry.yarnpkg.com/js-tokens/-/js-tokens-3.0.2.tgz#9866df395102130e38f7f996bceb65443209c25b"
 
 js-yaml@^3.11.0:
-  version "3.12.0"
-  resolved "https://registry.yarnpkg.com/js-yaml/-/js-yaml-3.12.0.tgz#eaed656ec8344f10f527c6bfa1b6e2244de167d1"
+  version "3.13.1"
+  resolved "https://registry.yarnpkg.com/js-yaml/-/js-yaml-3.13.1.tgz#aff151b30bfdfa8e49e05da22e7415e9dfa37847"
   dependencies:
     argparse "^1.0.7"
     esprima "^4.0.0"