Bump postcss from 8.2.13 to 8.4.31 in /docs

Bumps [postcss](https://github.com/postcss/postcss) from 8.2.13 to 8.4.31.
- [Release notes](https://github.com/postcss/postcss/releases)
- [Changelog](https://github.com/postcss/postcss/blob/main/CHANGELOG.md)
- [Commits](https://github.com/postcss/postcss/compare/8.2.13...8.4.31)

---
updated-dependencies:
- dependency-name: postcss
  dependency-type: direct:production
...

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

docs/yarn.lock

@@ -6633,10 +6633,10 @@ nanoid@^2.0.3:
   resolved "https://registry.yarnpkg.com/nanoid/-/nanoid-2.1.11.tgz#ec24b8a758d591561531b4176a01e3ab4f0f0280"
   integrity sha512-s/snB+WGm6uwi0WjsZdaVcuf3KJXlfGl2LcxgwkEwJF0D/BWzVWAZW/XY4bFaiR7s0Jk3FPvlnepg1H1b1UwlA==
 
-nanoid@^3.1.22:
-  version "3.1.23"
-  resolved "https://registry.yarnpkg.com/nanoid/-/nanoid-3.1.23.tgz#f744086ce7c2bc47ee0a8472574d5c78e4183a81"
-  integrity sha512-FiB0kzdP0FFVGDKlRLEQ1BgDzU87dy5NnzjeW9YZNt+/c3+q82EQDUwniSAUxp/F0gFNI1ZhKU1FqYsMuqZVnw==
+nanoid@^3.3.6:
+  version "3.3.7"
+  resolved "https://registry.yarnpkg.com/nanoid/-/nanoid-3.3.7.tgz#d0c301a691bc8d54efa0a2226ccf3fe2fd656bd8"
+  integrity sha512-eSRppjcPIatRIMC1U6UngP8XFcz8MQWGQdt1MTBQ7NaAmvXDfvNxbvWV3x2y6CdEUciCSsDHDQZbhYaB8QEo2g==
 
 nanomatch@^1.2.13, nanomatch@^1.2.9:
   version "1.2.13"
@@ -7331,6 +7331,11 @@ performance-now@^2.1.0:
   resolved "https://registry.yarnpkg.com/performance-now/-/performance-now-2.1.0.tgz#6309f4e0e5fa913ec1c69307ae364b4b377c9e7b"
   integrity sha1-Ywn04OX6kT7BxpMHrjZLSzd8nns=
 
+picocolors@^1.0.0:
+  version "1.0.0"
+  resolved "https://registry.yarnpkg.com/picocolors/-/picocolors-1.0.0.tgz#cb5bdc74ff3f51892236eaf79d68bc44564ab81c"
+  integrity sha512-1fygroTLlHu66zi26VoTDv8yRgm0Fccecssto+MhsZ0D/DGW2sm8E8AjW7NU5VVTRt5GxbeZ5qBuJr+HyLYkjQ==
+
 picomatch@^2.0.4, picomatch@^2.0.5, picomatch@^2.2.1:
   version "2.2.2"
   resolved "https://registry.yarnpkg.com/picomatch/-/picomatch-2.2.2.tgz#21f333e9b6b8eaff02468f5146ea406d345f4dad"
@@ -7768,13 +7773,13 @@ postcss@^7.0.0, postcss@^7.0.1, postcss@^7.0.14, postcss@^7.0.26, postcss@^7.0.2
     supports-color "^6.1.0"
 
 postcss@^8.2.10:
-  version "8.2.13"
-  resolved "https://registry.yarnpkg.com/postcss/-/postcss-8.2.13.tgz#dbe043e26e3c068e45113b1ed6375d2d37e2129f"
-  integrity sha512-FCE5xLH+hjbzRdpbRb1IMCvPv9yZx2QnDarBEYSN0N0HYk+TcXsEhwdFcFb+SRWOKzKGErhIEbBK2ogyLdTtfQ==
+  version "8.4.31"
+  resolved "https://registry.yarnpkg.com/postcss/-/postcss-8.4.31.tgz#92b451050a9f914da6755af352bdc0192508656d"
+  integrity sha512-PS08Iboia9mts/2ygV3eLpY5ghnUcfLV/EXTOW1E2qYxJKGGBUtNjN76FYHnMs36RmARn41bC0AZmn+rR0OVpQ==
   dependencies:
-    colorette "^1.2.2"
-    nanoid "^3.1.22"
-    source-map "^0.6.1"
+    nanoid "^3.3.6"
+    picocolors "^1.0.0"
+    source-map-js "^1.0.2"
 
 prepend-http@^1.0.0:
   version "1.0.4"
@@ -8849,6 +8854,11 @@ source-list-map@^2.0.0, source-list-map@^2.0.1:
   resolved "https://registry.yarnpkg.com/source-list-map/-/source-list-map-2.0.1.tgz#3993bd873bfc48479cca9ea3a547835c7c154b34"
   integrity sha512-qnQ7gVMxGNxsiL4lEuJwe/To8UnK7fAnmbGEEH8RpLouuKbeEm0lhbQVFIrNSuB+G7tVrAlVsZgETT5nljf+Iw==
 
+source-map-js@^1.0.2:
+  version "1.0.2"
+  resolved "https://registry.yarnpkg.com/source-map-js/-/source-map-js-1.0.2.tgz#adbc361d9c62df380125e7f161f71c826f1e490c"
+  integrity sha512-R0XvVJ9WusLiqTCEiGCmICCMplcCkIwwR11mOSD9CR5u+IXYdiseeEuXCVAjS54zqwkLcPNnmU4OeJ6tUrWhDw==
+
 source-map-resolve@^0.5.0, source-map-resolve@^0.5.2:
   version "0.5.3"
   resolved "https://registry.yarnpkg.com/source-map-resolve/-/source-map-resolve-0.5.3.tgz#190866bece7553e1f8f267a2ee82c606b5509a1a"