Validate devcontainer config file name

[Tpuljak]

Is your feature request related to a problem? Please describe.
The Devcontainer CLI will fail if the config file is not named .devcontainer.json or devcontainer.json. Currently, our TUI allows for any path to be entered which will fail during the build process if the condition is not met.

Error: Filename must be devcontainer.json or .devcontainer.json

Describe the solution you'd like
We should implement input validation that would inform the user during the creation process that the filename must be named .devcontainer.json or devcontainer.json.

[RS-labhub]

I have a solution to fix this issue. In case, if the fileName != requiredName, do I need to send an error message?

I'll try to raise a PR soon, after figuring out which file I have to change 😃

[Tpuljak]

do I need to send an error message?

@RS-labhub you need to use the validate function of the input to achieve this and the error will be displayed automatically.

[RS-labhub]

Got it!

[RS-labhub]

You can close this issue now

[Tpuljak]

@RS-labhub in the future, please add Closes #ISSUE_NUM in your PR description so it gets deleted automatically.