Add call out for Go 1.17 bump

Update alert banner for HashiConf Global 2021

```
go mod tidy
```

* Fail when the Packer Service datasource could not be found

* Update datasource/hcp-packer-image/data.go

Unregister packer-image-iteration datasource

hcp packer registry doc changes

This change temporarily renames the type of the packer-image-iteration
datasource to prevent it from being automatically registered by the
Packer plugin tooling. The datasource is fully functional, but not quite
ready for full usage. It will be updated in a future release.

Update HCP Packer registry image extraction, validation, publishing logic for registry capable plugins (#11221)

* Update handling of registry artifacts

This change uses the github.com/hashicorp/packer-plgin-sdk/packer/registryimage for querying
Artifact State for HCP Registry Image metadata. To handle the conversion
of the RPC response, mapstructure was introduced to conversion state
data into an registryimage.Image before publishing to a image bucket.

* Update to use registry image from packersdk

* Rename internal registry service pkg

* Update vendored plugins to latest version

* The latest release of Amazon, GoogleCompute, and Azure have support
  for publishing images to the HCP Packer registry.

Before change
```
=== Failed
=== FAIL: datasource/hcp-packer-iteration TestAccDatasource_HCPPackerIteration (1.97s)
    pluginacc.go:143: Error running plugin acceptance tests: Bad exit code. Logfile: packer_log_hcp_packer_iteration_datasource_basic_test.txt
        Logs can be found at /Users/wilkenrivera/Development/packer/datasource/hcp-packer-iteration/packer_log_hcp_packer_iteration_datasource_basic_test.txt
        and the acceptance test template can be found at /Users/wilkenrivera/Development/packer/datasource/hcp-packer-iteration/hcp_packer_iteration_datasource_basic_test.pkr.hcl

DONE 690 tests, 5 skipped, 1 failure in 387.912s
```

After change
```
=== SKIP: datasource/hcp-packer-iteration TestAccDatasource_HCPPackerIteration (0.00s)
    data_acc_test.go:35: Acceptance tests skipped unless envs "HCP_CLIENT_ID" and "HCP_CLIENT_SECRET" are set
```

* Update plugin directory check for ci

On CIRCLECI the default plugin direction is under `$HOME/.config/packer`
this changes updates the acctest just a bit to check if we are running
in a CIRCLECI env.

* Apply same logic to cleanup step

* Update Makefile

* Update .golangci.yml

Remove comment as version pinning is no longer needed.
Co-authored-by: Wilken Rivera <dev@wilkenrivera.com>

New data sources

allow datasources to use other datasources

create a null data source for testing. We can choose to document if we want to, but it's a convenience for us

add a test to catch cyclic datasource dependency, update tests to include out of order data sources, and update the code to clean up the returned diagnostics generated from the recursive evaluation

PR review comments

Add two new data sources -- hcp-packer-iteration and hcp-packer-image. These data sources together will allow users to query hcp_packer for the image_ids they need to use as source images to their builds, with a simple UI and clear outputs.
add quick and dirty acceptance test for hcp packer image iteration and hcp packer image data sources
PR review
linting

* up plugins and get rid of a dependency loop from packer to packer

Implement hcp packer data source. 

Co-authored-by: Sylvia Moss <moss@hashicorp.com>