Bump postcss from 7.0.7 to 7.0.39 in /fronts-client

Bumps [postcss](https://github.com/postcss/postcss) from 7.0.7 to 7.0.39.
- [Release notes](https://github.com/postcss/postcss/releases)
- [Changelog](https://github.com/postcss/postcss/blob/7.0.39/CHANGELOG.md)
- [Commits](postcss/postcss@7.0.7...7.0.39)

---
updated-dependencies:
- dependency-name: postcss
  dependency-type: indirect
...

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

fronts-client/yarn.lock

@@ -7961,6 +7961,11 @@ performance-now@^2.1.0:
   resolved "https://registry.yarnpkg.com/performance-now/-/performance-now-2.1.0.tgz#6309f4e0e5fa913ec1c69307ae364b4b377c9e7b"
   integrity sha1-Ywn04OX6kT7BxpMHrjZLSzd8nns=
 
+picocolors@^0.2.1:
+  version "0.2.1"
+  resolved "https://registry.yarnpkg.com/picocolors/-/picocolors-0.2.1.tgz#570670f793646851d1ba135996962abad587859f"
+  integrity sha512-cMlDqaLEqfSaW8Z7N5Jw+lyIW869EzT73/F5lhtY9cLGoVxSXznfgfXMO0Z5K0o0Q2TkTXq+0KFsdnSe3jDViA==
+
 picomatch@^2.0.4, picomatch@^2.2.1:
   version "2.3.0"
   resolved "https://registry.yarnpkg.com/picomatch/-/picomatch-2.3.0.tgz#f1f061de8f6a4bf022892e2d128234fb98302972"
@@ -8098,13 +8103,12 @@ postcss-value-parser@^4.0.2:
   integrity sha512-N7h4pG+Nnu5BEIzyeaaIYWs0LI5XC40OrRh5L60z0QjFsqGWcHcbkBvpe1WYpcIS9yQ8sOi/vIPt1ejQCrMVrg==
 
 postcss@^7.0.5, postcss@^7.0.6:
-  version "7.0.7"
-  resolved "https://registry.yarnpkg.com/postcss/-/postcss-7.0.7.tgz#2754d073f77acb4ef08f1235c36c5721a7201614"
-  integrity sha512-HThWSJEPkupqew2fnuQMEI2YcTj/8gMV3n80cMdJsKxfIh5tHf7nM5JigNX6LxVMqo6zkgQNAI88hyFvBk41Pg==
+  version "7.0.39"
+  resolved "https://registry.yarnpkg.com/postcss/-/postcss-7.0.39.tgz#9624375d965630e2e1f2c02a935c82a59cb48309"
+  integrity sha512-yioayjNbHn6z1/Bywyb2Y4s3yvDAeXGOyxqD+LnVOinq6Mdmd++SW2wUNVzavyyHxd6+DxzWGIuosg6P1Rj8uA==
   dependencies:
-    chalk "^2.4.1"
+    picocolors "^0.2.1"
     source-map "^0.6.1"
-    supports-color "^5.5.0"
 
 prelude-ls@~1.1.2:
   version "1.1.2"