fix: allow dots in usernames for non-GitHub git providers

[sanmaxdev]

Summary

• Updated the username validation regex in _get_username() to accept dots (.)
• Made the warning message provider-agnostic (not GitHub-specific)

GitLab and other git providers allow dots in usernames, but the existing regex only accepted alphanumeric characters and hyphens. This blocked module creation for users with dotted usernames on those platforms.

Changes

• nf_core/components/create.py: Modified regex to include . as a valid character in usernames
• Updated comment and warning text to refer generically to username validation

Verification

• ruff format — 1 file already formatted
• ruff check — All checks passed
• Regex validation — tested with @user, @user.name, @first.last, @user-name.last
• Import check — from nf_core.components.create import ComponentCreate passes

Closes #3655

[mashehu]

thanks for the fix.

Can you please add a test in tests/modules/test_create.py for it and also join the github org via the slack channel so the CI runs for you.

[sanmaxdev]

Thanks — added the requested regression coverage in tests/modules/test_create.py.

Verification:

• VIRTUAL_ENV= uv run --all-extras pytest tests/modules/test_create.py -k dotted_author_username --color=yes — 1 passed, 12 deselected
• VIRTUAL_ENV= uv run --all-extras ruff check nf_core/components/create.py tests/modules/test_create.py — passed
• VIRTUAL_ENV= uv run --all-extras ruff format --check nf_core/components/create.py tests/modules/test_create.py — passed