ENH: get_m and point.m property

[mwtoews]

Adds get_m and a m point property, available with GEOS 3.12 or later. For example:

import shapely

assert shapely.geos_version[0:2] >= (3, 12), shapely.geos_version_string

pt = shapely.from_wkt("POINT M (1 2 4)")
assert pt.m == shapely.get_m(pt) == 4.0

And similar to the z property:

pt = shapely.geometry.Point(1, 2)
shapely.get_m(pt)  # nan
pt.m
# raises: DimensionError: This point has no m coordinate.

Other checks to shapely/tests/geometry/test_point.py will be added after reworking Point().

[coveralls]

Pull Request Test Coverage Report for Build 8313966708

Warning: This coverage report may be inaccurate.

This pull request's base commit is no longer the HEAD commit of its target branch. This means it includes changes from outside the original pull request, including, potentially, unrelated coverage changes.

• For more information on this, see Tracking coverage changes with pull request builds.
• To avoid this issue with future PRs, see these Recommended CI Configurations.
• For a quick fix, rebase this PR at GitHub. Your next report should be accurate.

Details

• 9 of 10 (90.0%) changed or added relevant lines in 2 files are covered.
• 9 unchanged lines in 3 files lost coverage.
• Overall coverage increased (+0.3%) to 88.122%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
shapely/geometry/point.py	4	5	80.0%

Files with Coverage Reduction	New Missed Lines	%
shapely/creation.py	1	99.06%
shapely/geometry/base.py	4	92.22%
shapely/coordinates.py	4	90.48%

Totals
Change from base Build 8239849488:	0.3%
Covered Lines:	2619
Relevant Lines:	2972

---

💛 - Coveralls

[mwtoews]

@jorisvandenbossche do you have any idea why "Create a merge commit" is no longer enabled for this repository? This is usually my "go to" method, otherwise I can manually re-write this PR with one commit. Actually, "Squash and merge" is my "go to" method, so that's fine with me.