Fix issue with saving model

[teubert]

Fix issue where callback to save model causes lstm training to crash in newest version of tensorflow. change from prog_models hotfix v1.5.2

[github-actions[bot]]

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[codecov-commenter]

Codecov Report

Merging #65 (334b190) into dev (334b190) will not change coverage. The diff coverage is n/a.

:exclamation: Current head 334b190 differs from pull request most recent head 6f8d142. Consider uploading reports for the commit 6f8d142 to get more accurate results

@@           Coverage Diff           @@
##              dev      #65   +/-   ##
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  Coverage   84.17%   84.17%           
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  Files          99       99           
  Lines       10106    10106           
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  Hits         8507     8507           
  Misses       1599     1599