Port bwdist code to ImageMorphology

[tlnagy]

Fixes #883. This should not be merged until the following are complete:

BLOCKING

• Port bwdist code to ImageMorphology package ImageMorphology.jl#28 needs to be merged first
• Tag new release of ImageMorphology

[codecov]

Codecov Report

Merging #895 into master will increase coverage by 1.12%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master     #895      +/-   ##
==========================================
+ Coverage   76.38%   77.51%   +1.12%     
==========================================
  Files           9        8       -1     
  Lines         720      667      -53     
==========================================
- Hits          550      517      -33     
+ Misses        170      150      -20     

Impacted Files	Coverage Δ
src/Images.jl	0.00% <ø> (ø)

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 988cd87...62fe159. Read the comment docs.

[johnnychen94]

CI fails because pkg server, which is enabled since Julia 1.5, doesn't get synced yet, I'll retrigger the CI later today.

[johnnychen94]

I should have said that this workflow isn't perfect before merging this, e.g., Images v0.22.2 isn't compatible to ImageMorphology v0.2.6 because both export feature_transform/distance_transform, yet they're declared to be compatible 😢.

So I'll need to bump a patch version for this PR very quickly so that users don't hit this incompatibility.

However, we don't have a better choice until we take #898 seriously.

[timholy]

Yes, I've begun to think that semver + Pkg's version resolver really can't solve the problem fully. Adding a new method to ImageMorphology is not a breaking change in and of itself, only in the context of some other environment. It also runs into problems like JuliaLang/Pkg.jl#1251 (comment).