Provide proper releases via tags

Hi, I would appreciate it if you could make versioned releases via tags! Currently, I only see the `v1` tag - could you also create tags for the other releases?

This would allow us to better track which version of this action we are using because we pin this action to a full-length commit SHA.

Before:

```yaml
uses: dtolnay/rust-toolchain@efa25f7f19611383d5b0ccf2d1c8914531636bf9
```

After:

```yaml
uses: dtolnay/rust-toolchain@efa25f7f19611383d5b0ccf2d1c8914531636bf9 # v1.2.0
```

Dependabot can auto-update the version comment.