Bump postcss from 8.4.23 to 8.4.31 in /examples/slack-starter

Bumps [postcss](https://github.com/postcss/postcss) from 8.4.23 to 8.4.31.
- [Release notes](https://github.com/postcss/postcss/releases)
- [Changelog](https://github.com/postcss/postcss/blob/main/CHANGELOG.md)
- [Commits](postcss/postcss@8.4.23...8.4.31)

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

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

examples/slack-starter/yarn.lock

@@ -21,10 +21,10 @@
     enabled "2.0.x"
     kuler "^2.0.0"
 
-"@matrix-org/[email protected].4":
-  version "0.1.0-beta.4"
-  resolved "https://registry.yarnpkg.com/@matrix-org/matrix-sdk-crypto-nodejs/-/matrix-sdk-crypto-nodejs-0.1.0-beta.4.tgz#80456b2e2cc731982f0d3c6aece80cefa1ebb797"
-  integrity sha512-XjCp/tG3LRMxMj/MMZfypD5BtW3J1B6oXY2Og8Ed0SyU4uWdglalMwrBUKlDotJr0/Q/2OTspGjD+ytAzCspyw==
+"@matrix-org/[email protected].6":
+  version "0.1.0-beta.6"
+  resolved "https://registry.yarnpkg.com/@matrix-org/matrix-sdk-crypto-nodejs/-/matrix-sdk-crypto-nodejs-0.1.0-beta.6.tgz#0ecae51103ee3c107af0d6d0738f33eb7cc9857e"
+  integrity sha512-JXyrHuCVMydUGgSetWsfqbbvHj3aUMOX5TUghlMtLFromyEu7wIsNgYt7PjJ+k3WdF4GVABRy4P6GNjaEMy2uA==
   dependencies:
     https-proxy-agent "^5.0.1"
     node-downloader-helper "^2.1.5"
@@ -1046,7 +1046,7 @@ lru-cache@^7.10.1:
   integrity sha512-jumlc0BIUrS3qJGgIkWZsyfAM7NCWiBcCDhnd+3NNM5KbBmLTgHVfWBcg6W+rLUsIpzpERPsvwUP7CckAQSOoA==
 
 "matrix-appservice-bridge@file:../..":
-  version "8.1.1"
+  version "9.0.1"
   dependencies:
     "@alloc/quick-lru" "^5.2.0"
     axios "^0.27.2"
@@ -1058,7 +1058,7 @@ lru-cache@^7.10.1:
     is-my-json-valid "^2.20.5"
     js-yaml "^4.0.0"
     matrix-appservice "^2.0.0"
-    matrix-bot-sdk "npm:@vector-im/matrix-bot-sdk@^0.6.6-element.0"
+    matrix-bot-sdk "npm:@vector-im/matrix-bot-sdk@^0.6.6-element.1"
     nedb "^1.8.0"
     nopt "^5.0.0"
     p-queue "^6.6.2"
@@ -1079,12 +1079,12 @@ matrix-appservice@^2.0.0:
     js-yaml "^4.1.0"
     morgan "^1.10.0"
 
-"matrix-bot-sdk@npm:@vector-im/matrix-bot-sdk@^0.6.6-element.0":
-  version "0.6.6-element.0"
-  resolved "https://registry.yarnpkg.com/@vector-im/matrix-bot-sdk/-/matrix-bot-sdk-0.6.6-element.0.tgz#96e08bb434939fcbf7f771a47aa4a7d17632f601"
-  integrity sha512-Mx5SAv1zFXpkG+jbtbkadNMLjaxftnWBGCjKlNFlUDjcJPUIYxKd49jUGst/vdp/ysZYa0Dgk+V+E1qmKUa8bw==
+"matrix-bot-sdk@npm:@vector-im/matrix-bot-sdk@^0.6.6-element.1":
+  version "0.6.6"
+  resolved "https://registry.yarnpkg.com/@vector-im/matrix-bot-sdk/-/matrix-bot-sdk-0.6.6.tgz#e8a29d1404ab07e5d150b98222e9fbfc369752bb"
+  integrity sha512-MIZDCau+cWij3+NimTGOyVMDKb5EXO5wEEeS47wd+avr4ZN5EUO2pj2MLIytL9UYZ1OSlkZzECU4MRTL5B4wbQ==
   dependencies:
-    "@matrix-org/matrix-sdk-crypto-nodejs" "0.1.0-beta.4"
+    "@matrix-org/matrix-sdk-crypto-nodejs" "0.1.0-beta.6"
     "@types/express" "^4.17.13"
     another-json "^0.2.0"
     async-lock "^1.3.2"
@@ -1340,9 +1340,9 @@ pkginfo@^0.4.1:
   integrity sha512-8xCNE/aT/EXKenuMDZ+xTVwkT8gsoHN2z/Q29l80u0ppGEXVvsKRzNMbtKhg8LS8k1tJLAHHylf6p4VFmP6XUQ==
 
 postcss@^8.3.11:
-  version "8.4.23"
-  resolved "https://registry.yarnpkg.com/postcss/-/postcss-8.4.23.tgz#df0aee9ac7c5e53e1075c24a3613496f9e6552ab"
-  integrity sha512-bQ3qMcpF6A/YjR55xtoTr0jGOlnPOKAIMdOWiv0EIT6HVPEaJiJB4NLljSbiHoC2RX7DN5Uvjtpbg1NPdwv1oA==
+  version "8.4.31"
+  resolved "https://registry.yarnpkg.com/postcss/-/postcss-8.4.31.tgz#92b451050a9f914da6755af352bdc0192508656d"
+  integrity sha512-PS08Iboia9mts/2ygV3eLpY5ghnUcfLV/EXTOW1E2qYxJKGGBUtNjN76FYHnMs36RmARn41bC0AZmn+rR0OVpQ==
   dependencies:
     nanoid "^3.3.6"
     picocolors "^1.0.0"