fix failure on fork PRs

[alexkli]

Fixes #62.

For after checkout, always use local cloning and do not checkout
afterBranch as it will be automatically present in the local clone.

The git comparator also had to be adopted to always use the sha
instead of the git branch for after.

Add unit test fork.sh.

[github-actions]

🎉 Sizewatcher congratulates on the size improvement 📉:

   🎉 git -48.3% (390 kB => 202 kB)

✅ node_modules has no changes (46.8 MB)

Largest production node modules:

┌───────────────┬────────────┬───────┐
│ name          │ children   │ size  │
├───────────────┼────────────┼───────┤
│ simple-git    │ 0          │ 0.76M │
├───────────────┼────────────┼───────┤
│ js-yaml       │ 0          │ 0.28M │
├───────────────┼────────────┼───────┤
│ tmp           │ 0          │ 0.07M │
├───────────────┼────────────┼───────┤
│ xbytes        │ 0          │ 0.06M │
├───────────────┼────────────┼───────┤
│ glob          │ 0          │ 0.05M │
├───────────────┼────────────┼───────┤
│ debug         │ 0          │ 0.04M │
├───────────────┼────────────┼───────┤
│ deepmerge     │ 0          │ 0.03M │
├───────────────┼────────────┼───────┤
│ require-dir   │ 0          │ 0.02M │
├───────────────┼────────────┼───────┤
│ du            │ 0          │ 0.01M │
├───────────────┼────────────┼───────┤
│ @octokit/rest │ 0          │ 0.01M │
├───────────────┼────────────┼───────┤
│ + 1 modules   │            │       │
├───────────────┼────────────┼───────┤
│ 11 modules    │ 0 children │ 1.32M │
└───────────────┴────────────┴───────┘

✅ npm_package has no changes (20.3 kB)

Package contents:

📦  @adobe/sizewatcher@1.2.0
=== Tarball Contents === 
1.5kB  CHANGELOG.md                   
11.3kB LICENSE                        
25.5kB README.md                      
743B   index.js                       
5.9kB  lib/checkout.js                
3.9kB  lib/comparators/custom.js      
2.3kB  lib/comparators/git.js         
2.7kB  lib/comparators/node_modules.js
2.3kB  lib/comparators/npm_package.js 
5.9kB  lib/compare.js                 
1.7kB  lib/config.js                  
2.6kB  lib/github.js                  
3.9kB  lib/render.js                  
4.6kB  lib/report.js                  
2.6kB  lib/sizewatcher.js             
1.2kB  package.json                   
=== Tarball Details === 
name:          @adobe/sizewatcher                      
version:       1.2.0                                   
filename:      @adobe/sizewatcher-1.2.0.tgz            
package size:  20.3 kB                                 
unpacked size: 78.6 kB                                 
shasum:        a7376a1cdec05f60d1eabeebe5a07b39c1c3f990
integrity:     sha512-Z4c/4h6EU0ApP[...]/qJiU2FPgqBBg==
total files:   16

Notes

• PR branch: fix-forks @ 178158a
• Base branch: main
• Sizewatcher v1.2.0
• Effective Configuration:

limits:
  fail: 100%
  warn: 30%
  ok: '-10%'
report:
  githubComment: true
  githubStatus: false
comparators: {}

[github-actions]

🎉 Sizewatcher congratulates on the size improvement 📉:

   🎉 git -48.3% (390 kB => 202 kB)

✅ node_modules has no changes (46.8 MB)

Largest production node modules:

┌───────────────┬─────────────┬────────┐
│ name          │ children    │ size   │
├───────────────┼─────────────┼────────┤
│ @octokit/rest │ 35          │ 11.56M │
├───────────────┼─────────────┼────────┤
│ simple-git    │ 4           │ 0.86M  │
├───────────────┼─────────────┼────────┤
│ js-yaml       │ 3           │ 0.72M  │
├───────────────┼─────────────┼────────┤
│ glob          │ 12          │ 0.14M  │
├───────────────┼─────────────┼────────┤
│ tmp           │ 2           │ 0.13M  │
├───────────────┼─────────────┼────────┤
│ xbytes        │ 0           │ 0.06M  │
├───────────────┼─────────────┼────────┤
│ debug         │ 1           │ 0.05M  │
├───────────────┼─────────────┼────────┤
│ deepmerge     │ 0           │ 0.03M  │
├───────────────┼─────────────┼────────┤
│ require-dir   │ 0           │ 0.02M  │
├───────────────┼─────────────┼────────┤
│ du            │ 1           │ 0.01M  │
├───────────────┼─────────────┼────────┤
│ + 1 modules   │             │        │
├───────────────┼─────────────┼────────┤
│ 11 modules    │ 37 children │ 5.52M  │
└───────────────┴─────────────┴────────┘

✅ npm_package has no changes (20.4 kB)

Package contents:

📦  @adobe/sizewatcher@1.2.0
=== Tarball Contents === 
11.3kB LICENSE                        
5.9kB  lib/checkout.js                
5.9kB  lib/compare.js                 
1.7kB  lib/config.js                  
3.9kB  lib/comparators/custom.js      
2.3kB  lib/comparators/git.js         
2.6kB  lib/github.js                  
743B   index.js                       
2.7kB  lib/comparators/node_modules.js
2.3kB  lib/comparators/npm_package.js 
3.9kB  lib/render.js                  
4.6kB  lib/report.js                  
2.6kB  lib/sizewatcher.js             
1.2kB  package.json                   
1.5kB  CHANGELOG.md                   
25.5kB README.md                      
=== Tarball Details === 
name:          @adobe/sizewatcher                      
version:       1.2.0                                   
package size:  20.4 kB                                 
unpacked size: 78.6 kB                                 
shasum:        4423153124f45280f90c04fa7cfc409cd1e19155
integrity:     sha512-r3x3jomaoeXmV[...]7MOrDDfLmWuRA==
total files:   16

Notes

• PR branch: fix-forks @ 178158a
• Base branch: main
• Sizewatcher v1.2.0
• Effective Configuration:

limits:
  fail: 100%
  warn: 30%
  ok: '-10%'
report:
  githubComment: true
  githubStatus: false
comparators: {}

[coveralls]

Coverage increased (+1.3%) to 47.392% when pulling c789b52 on fix-forks into 7a4d505 on main.