Bump nunit.consolerunner.netcore from 3.20.2 to 3.21.0

---
updated-dependencies:
- dependency-name: nunit.consolerunner.netcore
  dependency-version: 3.21.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

.config/dotnet-tools.json

@@ -17,7 +17,7 @@
       "rollForward": false
     },
     "nunit.consolerunner.netcore": {
-      "version": "3.20.2",
+      "version": "3.21.0",
       "commands": [
         "nunit"
       ],