[x/blog] content: ensure better semver versions in the v2 modules article
[x/blog] content: ensure better semver versions in the v2 modules article

The Semantic Versioning specification at https://semver.org uses dots to
separate the numeric part of a pre-release version from the non-numeric
to ensure that they sort correctly.  Make the article comply.

Change-Id: I7a366e4c180f5048b1cc19cdf3e66c515989e4ab
Reviewed-on: https://go-review.googlesource.com/c/blog/+/206157
Reviewed-by: Jean de Klerk <605b93664484fed1e671a07bff68da39e73d0174@google.com>
Reviewed-by: Jay Conrod <f3fadaedc813344da5ec13b41e26596889cc5baa@google.com>
Reviewed-by: Bryan C. Mills <1c8aad60184261ccede67f5c63a0d2a3bf3c9ff4@google.com>
X-Blog-Commit: 97ded1e093da2a216dd3c479bdb3846e0976d52a

golang/website,golang/website,golang/website,golang/website,golang/website,golang/website,golang/website