chore(deps): bump postcss from 7.0.27 to 7.0.39 in /packages/docs

Bumps [postcss](https://github.com/postcss/postcss) from 7.0.27 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](https://github.com/postcss/postcss/compare/7.0.27...7.0.39)

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

Signed-off-by: dependabot[bot] <support@github.com>

packages/docs/yarn.lock

@@ -2510,6 +2510,11 @@ 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@^2.0.5, picomatch@^2.0.7:
   version "2.2.1"
   resolved "https://registry.yarnpkg.com/picomatch/-/picomatch-2.2.1.tgz#21bac888b6ed8601f831ce7816e335bc779f0a4a"
@@ -2543,13 +2548,12 @@ postcss-value-parser@^4.0.2:
   integrity sha512-N7h4pG+Nnu5BEIzyeaaIYWs0LI5XC40OrRh5L60z0QjFsqGWcHcbkBvpe1WYpcIS9yQ8sOi/vIPt1ejQCrMVrg==
 
 postcss@^7.0.26, postcss@^7.0.7:
-  version "7.0.27"
-  resolved "https://registry.yarnpkg.com/postcss/-/postcss-7.0.27.tgz#cc67cdc6b0daa375105b7c424a85567345fc54d9"
-  integrity sha512-WuQETPMcW9Uf1/22HWUWP9lgsIC+KEHg2kozMflKjbeUtw9ujvFX6QmIfozaErDkmLWS9WEnEdEe6Uo9/BNTdQ==
+  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 "^2.4.2"
+    picocolors "^0.2.1"
     source-map "^0.6.1"
-    supports-color "^6.1.0"
 
 pretty-hrtime@^1.0.3:
   version "1.0.3"
@@ -3179,13 +3183,6 @@ supports-color@^5.3.0:
   dependencies:
     has-flag "^3.0.0"
 
-supports-color@^6.1.0:
-  version "6.1.0"
-  resolved "https://registry.yarnpkg.com/supports-color/-/supports-color-6.1.0.tgz#0764abc69c63d5ac842dd4867e8d025e880df8f3"
-  integrity sha512-qe1jfm1Mg7Nq/NSh6XE24gPXROEVsWHxC1LIx//XNlD9iw7YZQGjZNjYN7xGaEG6iKdA8EtNFW6R0gjnVXp+wQ==
-  dependencies:
-    has-flag "^3.0.0"
-
 supports-color@^7.1.0:
   version "7.1.0"
   resolved "https://registry.yarnpkg.com/supports-color/-/supports-color-7.1.0.tgz#68e32591df73e25ad1c4b49108a2ec507962bfd1"