Documentation (GoogleCloudPlatform#10012)

* duplicate Composer 2 argument reference

* remove fields that are not supported in Composer 3

* move fields that are new in Composer 3 to Composer 3 section only

* make suggested changes, add description if new versioning schema

* Update mmv1/third_party/terraform/website/docs/r/composer_environment.html.markdown, remove outdated info

Co-authored-by: Pavel Salnikov <[email protected]>

* Update mmv1/third_party/terraform/website/docs/r/composer_environment.html.markdown

Co-authored-by: Pavel Salnikov <[email protected]>

* Update mmv1/third_party/terraform/website/docs/r/composer_environment.html.markdown

Co-authored-by: Pavel Salnikov <[email protected]>

* Update mmv1/third_party/terraform/website/docs/r/composer_environment.html.markdown

Co-authored-by: Pavel Salnikov <[email protected]>

* Update mmv1/third_party/terraform/website/docs/r/composer_environment.html.markdown

Co-authored-by: Pavel Salnikov <[email protected]>

* Update mmv1/third_party/terraform/website/docs/r/composer_environment.html.markdown

Co-authored-by: Pavel Salnikov <[email protected]>

* Update mmv1/third_party/terraform/website/docs/r/composer_environment.html.markdown

Co-authored-by: Pavel Salnikov <[email protected]>

* Update mmv1/third_party/terraform/website/docs/r/composer_environment.html.markdown

Co-authored-by: Pavel Salnikov <[email protected]>

* Update mmv1/third_party/terraform/website/docs/r/composer_environment.html.markdown

Co-authored-by: Pavel Salnikov <[email protected]>

* Update mmv1/third_party/terraform/website/docs/r/composer_environment.html.markdown

Co-authored-by: Pavel Salnikov <[email protected]>

* add notice that composer 3 is not yet released.

* Update mmv1/third_party/terraform/website/docs/r/composer_environment.html.markdown

Co-authored-by: Stephen Lewis (Burrows) <[email protected]>

* specify composer version in section links.

* specify composer version in composer 1 documentation links

* add section links in composer 2 argument reference

* add section links in composer 3 argument reference

* Update mmv1/third_party/terraform/website/docs/r/composer_environment.html.markdown

Co-authored-by: Pavel Salnikov <[email protected]>

* Update mmv1/third_party/terraform/website/docs/r/composer_environment.html.markdown

Co-authored-by: Pavel Salnikov <[email protected]>

* Update mmv1/third_party/terraform/website/docs/r/composer_environment.html.markdown

Co-authored-by: Pavel Salnikov <[email protected]>

* Update mmv1/third_party/terraform/website/docs/r/composer_environment.html.markdown

Co-authored-by: Pavel Salnikov <[email protected]>

* Update mmv1/third_party/terraform/website/docs/r/composer_environment.html.markdown

Co-authored-by: Pavel Salnikov <[email protected]>

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Co-authored-by: Pavel Salnikov <[email protected]>
Co-authored-by: Stephen Lewis (Burrows) <[email protected]>