hcl2template: check bucket name at parse-time

Not validating the bucket's name during parse leads to configurations
being marked as valid, even if the bucket name is not, which will fail
during a real build afterwards.

To avoid this problem and fail with an error as quickly as possible, we
add a check during parsing, so that it gets reported for validate as
well.

Cut release 1.10.1

Update spacing for flags within Help text

Before Change
```

Options:
  - path <path>: install the plugin from a locally-sourced plugin binary. This
                 installs the plugin where a normal invocation would, but will
                 not try to download it from a remote location, and instead
                 install the binary in the Packer plugins path.
                 This option cannot be specified with a version constraint.
  - force:       forces reinstallation of plugins, even if already installed.

```

After Change
```
Options:
  -path <path>                  Install the plugin from a locally-sourced plugin binary.
                                This installs the plugin where a normal invocation would, but will
                                not try to download it from a remote location, and instead
                                install the binary in the Packer plugins path. This option cannot
                                be specified with a version constraint.
  -force                        Forces reinstallation of plugins, even if already installed.
```

version: cut v1.9.5

Merge pull request hashicorp#12600 from hashicorp/backport/bump_go/un…

…iformly-classic-yeti

This pull request was automerged via backport-assistant

Cut 1.9.3 release

Cut v1.9.2 release

version: cut 1.9.1 on VERSION file

cut release 1.9.0

Update CHANGELOG