chore(deps): bump postcss from 7.0.27 to 7.0.39 in /docs (sagalbot#1580)

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

docs/yarn.lock

@@ -5723,6 +5723,11 @@ 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==
+
 pify@^2.0.0:
  version "2.3.0"
  resolved "https://registry.yarnpkg.com/pify/-/pify-2.3.0.tgz#ed141a6ac043a849ea588498e7dca8b15330e90c"
@@ -6111,13 +6116,12 @@ postcss-value-parser@^4.0.2, postcss-value-parser@^4.0.3:
  integrity sha512-N7h4pG+Nnu5BEIzyeaaIYWs0LI5XC40OrRh5L60z0QjFsqGWcHcbkBvpe1WYpcIS9yQ8sOi/vIPt1ejQCrMVrg==
 
 postcss@^7.0.0, postcss@^7.0.1, postcss@^7.0.14, postcss@^7.0.26, postcss@^7.0.27, postcss@^7.0.5, postcss@^7.0.6:
- 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"
 
 prepend-http@^1.0.0:
  version "1.0.4"