tests: simplify and reduce the strictness of version string regex patterns

tests: simplify and reduce the strictness of version string regex patterns

It seems like every release there's some new problem with parsing the
version strings in tests. Let's reduce the strictness of the patterns
to avoid future test failures and accept the following version schemes:

X.Y
X.Y.Z
X.Y-devel
X.Y-rcZ

Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>