ci(github): update build + release workflow

This commit updates the build and release workflow to enable multi-arch
builds and releases.

A number of Rust-specific actions have been added, namely rust-cache to
handle cargo caching and actions-rust-cross to handle cross-compilation.

A release-dry-run target has been added to run on master which should
help catch any issues in release workflow changes early.

Releases drop goreleaser entirely in favour of action-gh-release which
was already in use to add msi installers to the releases previously
created by goreleaser.

.github/ISSUE_TEMPLATE/feature_request.yml

@@ -1,6 +1,6 @@
 name: Feature request
 description: Suggest a new feature
-labels: [ enhancement ]
+labels: [enhancement]
 title: "[FEAT]: "
 body:
   - type: dropdown