(release/1) Allow set-version.php to generate upgraders for major/minor increments

[totten]

Overview

The utility, tools/bin/scripts/set-version.php, is used to generate
boilerplate files for incremental updates. This change improves
compatibility with the version realignment.

Before

The set-version.php script supports incrementing the third digit only.

Specifically, it:

• Sets the current version number in xml/version.xml (etal). (This is required for all version bumps.)
• Generates an incremental SQL upgrade file. (This is required for all version bumps.)

After

The set-version.php script supports incrementing the first, second, and/or third digit.

Specifically, it generates the same files as before, and:

• Generates an incremental PHP upgrade file. (This is only required when increasing the first or second digit.)

Comments

To test this, I locally produced a series of upgrade steps:

./tools/bin/scripts/set-version.php 5.0.alpha1 --no-commit
./tools/bin/scripts/set-version.php 5.0.alpha2 --no-commit
./tools/bin/scripts/set-version.php 5.0.0 --no-commit
./tools/bin/scripts/set-version.php 5.0.1 --no-commit
./tools/bin/scripts/set-version.php 5.1.alpha1 --no-commit
./tools/bin/scripts/set-version.php 5.1.beta1 --no-commit

Then, I ran cv upgrade:db -vvv (as
both dry-run and normal-run) and verified that the expected upgrade steps
were used.

[eileenmcnaughton]

I'm merging this based on @totten's testing (described above) & a skim of the code. I believe that any impact this has would flush itself out in the rc process & on dev installs & the change seems fairly trivial.

I note this does not commit us to the version re-alignment which I support as long as all messaging at the time is around this being no change from the normal process other than a minor renaming. There is a prospect for confusion & I think that if we can't keep that message clear & consistent the case for the version re-alignment cannot be made.