Bump fsdocs-tool from 21.0.0-beta-005 to 21.0.0

---
updated-dependencies:
- dependency-name: fsdocs-tool
  dependency-version: 21.0.0
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

Author: dependabot[bot]

.config/dotnet-tools.json

@@ -3,7 +3,7 @@
   "isRoot": true,
   "tools": {
     "fsdocs-tool": {
-      "version": "21.0.0-beta-005",
+      "version": "21.0.0",
       "commands": [
         "fsdocs"
       ],