Add editorconfig validation #3761

Job	Run time
Build (ubuntu-latest, linux)	2m 6s
Tidy Go Modules	24s
Build (windows-latest, windows)	6m 6s
Build (macos-latest, macos)	1m 14s
Docker Lint	24s
[lint] demo-context	11s
[k3s] demo-helmfile	42s
[localstack] demo-localstack	2m 21s
[lint] quick-start-advanced	6s
Acceptance Tests (ubuntu-latest, linux)	3m 34s
[validate] demo-context	6s
Acceptance Tests (windows-latest, windows)	7m 36s
[mock-linux] examples/demo-atlantis	12s
[validate] demo-localstack	6s
Acceptance Tests (macos-latest, macos)	2m 29s
[mock-linux] examples/demo-component-versions	12s
[validate] demo-stacks	4s
[validate] demo-helmfile	6s
[validate] quick-start-advanced	4s
[validate] quick-start-simple	4s
[mock-linux] examples/demo-context	17s
[mock-linux] examples/demo-vendoring	24s
[mock-linux] tests/fixtures/scenarios/complete	21s
[mock-windows] examples/demo-atlantis	16s
[mock-windows] examples/demo-component-versions	45s
[mock-windows] examples/demo-context	27s
[mock-windows] examples/demo-vendoring	1m 2s
[mock-windows] tests/fixtures/scenarios/complete	1m 3s
[mock-macos] examples/demo-atlantis	11s
[mock-macos] examples/demo-component-versions	17s
[mock-macos] examples/demo-context	15s
[mock-macos] examples/demo-vendoring	28s
[mock-macos] tests/fixtures/scenarios/complete	32s
release	0s
	34m 25s

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