azurelinux-repos: fix dist tag date extraction for tilde-only forms

[reubeno]

The date extraction logic split on '.' to get the last segment, which worked for dist tags like .azl4~bootstrap.20260303 but failed for .azl4~20260412 where there is no dot before the date.

Replace the awk dot-split with grep -oE to extract the 8-digit date directly from anywhere in the dist tag.

_Verification: verified with both a stage1 and stage2 style dist tag locally via azldev; verified via CT + koji with scratch builds against both stage1 and stage2 tags, manually downloaded and inspected built RPMs.

[Copilot]

Pull request overview

Note

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Fixes dist tag date extraction in azurelinux-repos.spec so that BASE_REPO_URI computation works for both dotted and tilde-only dist tag formats.

Changes:

• Bump Release from 4 to 5.
• Replace dot-splitting awk logic with regex extraction of an 8-digit date from %{dist}.
• Add changelog entry documenting the behavior change.

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[Copilot]

grep -oE will output all 8-digit matches, potentially producing multiple lines in date_segment (e.g., newline-separated). That would make base_repo_uri malformed and could lead to unexpected behavior when %{dist} ever contains more than one 8-digit sequence. Prefer constraining to a single match (e.g., first match via grep -m1 -oE ... or piping to head -n1) and/or stripping newlines before using it in the URL.

Suggested change

	# Extract an 8-digit date stamp from %%dist.
	# Handles both dotted forms (e.g. ".azl4~bootstrap.20260303") and tilde-only forms (e.g. ".azl4~20260412").
	# If no 8-digit date is found, fall back to a hard-coded URI.
	date_segment=$(echo '%{dist}' | grep -oE '[0-9]{8}')
	# Extract the first 8-digit date stamp from %%dist.
	# Handles both dotted forms (e.g. ".azl4~bootstrap.20260303") and tilde-only forms (e.g. ".azl4~20260412").
	# If no 8-digit date is found, fall back to a hard-coded URI.
	date_segment=$(echo '%{dist}' | grep -oE '[0-9]{8}' | head -n1)