fix: correct README.yaml indentation and test atmos configs (#96)

* fix: correct indentation in README.yaml blockquote

* fix: remove ./ prefix from base_path in test atmos configs

* Add caching for .terraform directory

Added caching for .terraform directory to improve performance.

* Rename retrieved plan filename format

* Fix retrieved plan filename and reintroduce caching

---------

Co-authored-by: Igor Rodionov <496956+goruha@users.noreply.github.com>

Author: milldr

README.yaml

@@ -189,9 +189,9 @@ usage: |-
   To enable plan diff mode, set the `plan-diff` input to `true`.
 
   > [!IMPORTANT]
-> When plan-diff is disabled, the action will apply the stored plan without re-validating it.
-> This may result in unintended changes if the underlying infrastructure has been modified between the plan and apply steps.
-> Additionally, stored plans are single-use: even if an apply operation fails for any reason, the plan becomes outdated and cannot be reused.
+  > When plan-diff is disabled, the action will apply the stored plan without re-validating it.
+  > This may result in unintended changes if the underlying infrastructure has been modified between the plan and apply steps.
+  > Additionally, stored plans are single-use: even if an apply operation fails for any reason, the plan becomes outdated and cannot be reused.
 
   ### Workflow example
 

tests/opentofu/atmos.yaml

@@ -15,7 +15,7 @@
 # are independent settings (supporting both absolute and relative paths).
 # If `base_path` is provided, `components.terraform.base_path`, `components.helmfile.base_path`, `stacks.base_path` and `workflows.base_path`
 # are considered paths relative to `base_path`.
-base_path: "./tests/opentofu"
+base_path: "tests/opentofu"
 
 aliases:
   tofu: terraform

tests/terraform/atmos.yaml

@@ -15,7 +15,7 @@
 # are independent settings (supporting both absolute and relative paths).
 # If `base_path` is provided, `components.terraform.base_path`, `components.helmfile.base_path`, `stacks.base_path` and `workflows.base_path`
 # are considered paths relative to `base_path`.
-base_path: "./tests/terraform"
+base_path: "tests/terraform"
 
 components:
   terraform: