fix for Project targeting net5.0 won't build Splat.Drawing

[ChrisPulman]

What kind of change does this PR introduce?

fix for #809

What is the current behaviour?

Net5.0 and Net6.0 libraries have no targets

What is the new behaviour?

Added targets for Net5.0 and Net6.0 libraries

What might this PR break?

none expected

Please check if the PR fulfils these requirements

• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)

Other information:

[glennawatson]

Need a better PR description, what is it you are fixing ;)

[codecov]

Codecov Report

Merging #810 (84d2d72) into main (6b87b77) will not change coverage.
The diff coverage is n/a.

❗ Current head 84d2d72 differs from pull request most recent head 7dee7a8. Consider uploading reports for the commit 7dee7a8 to get more accurate results

@@           Coverage Diff           @@
##             main     #810   +/-   ##
=======================================
  Coverage   74.36%   74.36%           
=======================================
  Files          99       99           
  Lines        4970     4970           
=======================================
  Hits         3696     3696           
  Misses       1274     1274           

Impacted Files	Coverage Δ
.../Platforms/ServiceLocationDrawingInitialization.cs	0.00% <ø> (ø)

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[github-actions]

This pull request has been automatically locked since there has not been any recent activity after it was closed. Please open a new issue for related bugs.