fix docs build

[CagtayFabry]

Changes

weekly build: https://github.com/BAMWelDX/weldx/runs/5715407058?check_suite_focus=true

nbsphinx.NotebookError: AttributeError in tutorials/measurement_example.ipynb:
module 'jinja2.utils' has no attribute 'escape'

Checks

• updated doc/

[github-actions]

Unit Test Results

       1 files  ±0         1 suites  ±0   4m 23s ⏱️ +6s
2 158 tests ±0  2 158 ✔️ ±0  0 💤 ±0  0 ❌ ±0 

Results for commit a09efff. ± Comparison against base commit 487218c.

♻️ This comment has been updated with latest results.

[codecov]

Codecov Report

Merging #729 (a09efff) into master (487218c) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #729   +/-   ##
=======================================
  Coverage   95.88%   95.88%           
=======================================
  Files          92       92           
  Lines        6496     6496           
=======================================
  Hits         6229     6229           
  Misses        267      267           

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