Bump minimatch, @microsoft/sp-build-web, @microsoft/sp-webpart-workbench and gulp

Bumps [minimatch](https://github.com/isaacs/minimatch) to 3.0.4 and updates ancestor dependencies [minimatch](https://github.com/isaacs/minimatch), [@microsoft/sp-build-web](http://aka.ms/spfx), [@microsoft/sp-webpart-workbench](http://aka.ms/spfx) and [gulp](https://github.com/gulpjs/gulp). These dependencies need to be updated together.


Updates `minimatch` from 0.2.14 to 3.0.4
- [Release notes](https://github.com/isaacs/minimatch/releases)
- [Commits](https://github.com/isaacs/minimatch/compare/v0.2.14...v3.0.4)

Updates `@microsoft/sp-build-web` from 1.10.0 to 1.15.2

Updates `@microsoft/sp-webpart-workbench` from 1.10.0 to 1.12.1

Updates `gulp` from 3.9.1 to 4.0.2
- [Release notes](https://github.com/gulpjs/gulp/releases)
- [Changelog](https://github.com/gulpjs/gulp/blob/master/CHANGELOG.md)
- [Commits](https://github.com/gulpjs/gulp/compare/v3.9.1...v4.0.2)

---
updated-dependencies:
- dependency-name: minimatch
  dependency-type: indirect
- dependency-name: "@microsoft/sp-build-web"
  dependency-type: direct:development
- dependency-name: "@microsoft/sp-webpart-workbench"
  dependency-type: direct:development
- dependency-name: gulp
  dependency-type: direct:development
...

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

samples/react-covid19-info/package.json

@@ -37,12 +37,12 @@
     "@types/react": "16.8.8"
   },
   "devDependencies": {
-    "@microsoft/sp-build-web": "1.10.0",
+    "@microsoft/sp-build-web": "1.15.2",
     "@microsoft/sp-tslint-rules": "1.10.0",
     "@microsoft/sp-module-interfaces": "1.10.0",
-    "@microsoft/sp-webpart-workbench": "1.10.0",
+    "@microsoft/sp-webpart-workbench": "1.12.1",
     "@microsoft/rush-stack-compiler-3.3": "0.3.5",
-    "gulp": "~3.9.1",
+    "gulp": "~4.0.2",
     "@types/chai": "3.4.34",
     "@types/mocha": "2.2.38",
     "ajv": "~5.2.2"