Add checks for correct semantic version of Python

[michaelsaki]

🗣 Description

Now if a user enters an incorrect semantic version of Python they will get the following message: "Invalid version of Python: Python follows semantic versioning, so any version string that is not a valid semantic version is an invalid version of Python."

💭 Motivation and context

This PR will address the issue here: https://github.com/cisagov/skeleton-generic/issues/167.

🧪 Testing

I tested this by making a testing script that verified the following examples were valid or invalid semantic versions:

Valid Semantic Versions

0.0.4
1.2.3
10.20.30
1.1.2-prerelease+meta
1.1.2+meta
1.1.2+meta-valid
1.0.0-alpha
1.0.0-beta
1.0.0-alpha.beta
1.0.0-alpha.beta.1
1.0.0-alpha.1
1.0.0-alpha0.valid
1.0.0-alpha.0valid
1.0.0-alpha-a.b-c-somethinglong+build.1-aef.1-its-okay
1.0.0-rc.1+build.1
2.0.0-rc.1+build.123
1.2.3-beta
10.2.3-DEV-SNAPSHOT
1.2.3-SNAPSHOT-123
1.0.0
2.0.0
1.1.7
2.0.0+build.1848
2.0.1-alpha.1227
1.0.0-alpha+beta
1.2.3----RC-SNAPSHOT.12.9.1--.12+788
1.2.3----R-S.12.9.1--.12+meta
1.2.3----RC-SNAPSHOT.12.9.1--.12
1.0.0+0.build.1-rc.10000aaa-kk-0.1
99999999999999999999999.999999999999999999.99999999999999999
1.0.0-0A.is.legal

Invalid Semantic Versions

1
1.2
1.2.3-0123
1.2.3-0123.0123
1.1.2+.123
+invalid
-invalid
-invalid+invalid
-invalid.01
alpha
alpha.beta
alpha.beta.1
alpha.1
alpha+beta
alpha_beta
alpha.
alpha..
beta
1.0.0-alpha_beta
-alpha.
1.0.0-alpha..
1.0.0-alpha..1
1.0.0-alpha...1
1.0.0-alpha....1
1.0.0-alpha.....1
1.0.0-alpha......1
1.0.0-alpha.......1
01.1.1
1.01.1
1.1.01
1.2
1.2.3.DEV
1.2-SNAPSHOT
1.2.31.2.3----RC-SNAPSHOT.12.09.1--..12+788
1.2-RC-SNAPSHOT
-1.0.3-gamma+b7718
+justmeta
9.8.7+meta+meta
9.8.7-whatever+meta+meta
99999999999999999999999.999999999999999999.99999999999999999----RC-SNAPSHOT.12.09.1--------------------------------..12

✅ Pre-approval checklist

• [x] This PR has an informative and human-readable title.
• [x] Changes are limited to a single goal - eschew scope creep!
• [x] All relevant type-of-change labels have been added.
• [x] I have read the CONTRIBUTING document.
• [x] These code changes follow cisagov code standards.
• [x] All new and existing tests pass.

✅ Pre-merge checklist

• [ ] Revert dependencies to default branches.
• [ ] Finalize version.

✅ Post-merge checklist

• [ ] Create a release.