Improve error message when the user tries to freeze a Dockerfile to Seqera Containers

[itrujnara]

Reproduction

Run the command

wave -f Dockerfile --freeze

with any valid Dockerfile.

The current output is

Wave invalid response: [400] {"message":"Attribute `buildRepository` must be specified when using freeze mode [1]"}

Explanation

The error message does not explain the source of the issue (especially since --freeze works without --build-repository in some use cases).

Proposed solution

Change the error message to the following:

Attribute `buildRepository` must be specified when using freeze mode with a Dockerfile. Only Conda and pip packages can be frozen to Seqera Containers.

or OWTTE.

[munishchouhan]

@itrujnara thanks for reporting the issue
--freeze works without --build-repository only for conda packages and not for custom Dockerfile
That is a special case, where we use community.seqera.io as --build-repository to support community.

freeze main purpose is to store for long duration, in user specified repository
--build-repository is always required when using --freeze