Bump actions/cache from 2 to 4

Bumps [actions/cache](https://github.com/actions/cache) from 2 to 4.
- [Release notes](https://github.com/actions/cache/releases)
- [Changelog](https://github.com/actions/cache/blob/main/RELEASES.md)
- [Commits](https://github.com/actions/cache/compare/v2...v4)

---
updated-dependencies:
- dependency-name: actions/cache
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

.github/workflows/build.yml

@@ -39,7 +39,7 @@
       'with':
         'node-version': '${{ env.NODE_VERSION }}'
     - 'name': 'Set up Go modules cache'
-      'uses': 'actions/cache@v2'
+      'uses': 'actions/cache@v4'
       'with':
         'path': '~/go/pkg/mod'
         'key': "${{ runner.os }}-go-${{ hashFiles('go.sum') }}"
@@ -48,7 +48,7 @@
       'id': 'npm-cache'
       'run': 'echo "::set-output name=dir::$( npm config get cache )"'
     - 'name': 'Set up npm cache'
-      'uses': 'actions/cache@v2'
+      'uses': 'actions/cache@v4'
       'with':
         'path': '${{ steps.npm-cache.outputs.dir }}'
         'key': "${{ runner.os }}-node-${{ hashFiles('client/package-lock.json') }}"
@@ -80,7 +80,7 @@
       'with':
         'node-version': '${{ env.NODE_VERSION }}'
     - 'name': 'Set up Go modules cache'
-      'uses': 'actions/cache@v2'
+      'uses': 'actions/cache@v4'
       'with':
         'path': '~/go/pkg/mod'
         'key': "${{ runner.os }}-go-${{ hashFiles('go.sum') }}"
@@ -89,7 +89,7 @@
       'id': 'npm-cache'
       'run': 'echo "::set-output name=dir::$(npm config get cache)"'
     - 'name': 'Set up npm cache'
-      'uses': 'actions/cache@v2'
+      'uses': 'actions/cache@v4'
       'with':
         'path': '${{ steps.npm-cache.outputs.dir }}'
         'key': "${{ runner.os }}-node-${{ hashFiles('client/package-lock.json') }}"