fix pint 0.21 related errors

[CagtayFabry]

Changes

• compatibility with pint=0.21 and earlier versions
• add units to some newly supported numpy functions

Related Issues

closes #872

Checks

• updated CHANGELOG.md
• updated tests/

[github-actions]

Test Results

2 189 tests  ±0   2 188 ✔️ +125   3m 3s ⏱️ + 1m 1s
       1 suites ±0          1 💤 ±    0 
       1 files   ±0          0 ❌  - 125 

Results for commit ee167b3. ± Comparison against base commit c2ee9b1.

♻️ This comment has been updated with latest results.

[codecov]

Codecov Report

Merging #876 (ee167b3) into master (c2ee9b1) will not change coverage.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master     #876   +/-   ##
=======================================
  Coverage   96.51%   96.51%           
=======================================
  Files          94       94           
  Lines        6283     6283           
=======================================
  Hits         6064     6064           
  Misses        219      219           

Impacted Files	Coverage Δ
weldx/geometry.py	96.62% <100.00%> (ø)

[CagtayFabry]

I looked into the mypy errors but could not figure out what the best way to implement type hints is now

Unfortunately the documentation for this is lacking in pint, so leaving as is for now (mypy passes with pint=0.20)