Variables support

This adds support for Query Variables. They now call /variable endpoint instead of /search.

If you've used this datasource with Query Variables before, it will stop working for you probably. Open an issue for support.

What's Changed

• Upgrade grafana deps to v8.1.x by @simPod in #193
• Bump tmpl from 1.0.4 to 1.0.5 by @dependabot in #194
• Upgrade Grafana deps to v8.1.5 by @simPod in #195
• Do not use event.currentTarget.name as it's fragile by @simPod in #196
• Use proper VariableQuery variable in VariableQueryEditor::checkValidJSON() by @simPod in #197
• Do not override MetricFindValue type by @simPod in #198
• Use rxjs by @simPod in #199
• Upgrade @types/lodash to 4.14.176 by @simPod in #210
• Upgrade rxjs to 7.4 by @simPod in #211
• Add workflow_dispatch trigger to GA by @simPod in #212
• Use actions/setup-node@v2 by @simPod in #214
• Run CI on node 16 by @simPod in #216
• Use Yarn v3 by @simPod in #215
• Fix Readme typo by @chenyahui in #220
• Add types to DataSource by @simPod in #228
• Bump to Grafana 8.3.x deps by @simPod in #227
• Add support for querying variables by @simPod in #200
• Replace stale bot with GA by @simPod in #229

New Contributors

• @chenyahui made their first contribution in #220

Full Changelog: 0.3.0...0.4.0