Separate parameter support

Updated in this version:

• Separate custom params #55 - Huge thanks to @Filiecs
• Integrate codecov #42

Also these bumps are in:

• Bump @zeit/ncc from 0.20.5 to 0.21.0 dependencies javascript #54
• Bump husky from 4.0.0-beta.5 to 4.2.1 dependencies javascript #53
• Bump eslint-plugin-flowtype from 4.5.2 to 4.6.0 dependencies javascript #52
• Bump eslint from 6.7.2 to 6.8.0 dependencies javascript #51
• Bump eslint-plugin-import from 2.19.1 to 2.20.1 dependencies javascript #50
• Bump @babel/core from 7.7.5 to 7.8.4 dependencies javascript #49
• Bump lint-staged from 9.5.0 to 10.0.7 dependencies javascript #48
• Bump eslint-config-prettier from 6.7.0 to 6.10.0 dependencies javascript #47
• Bump eslint-plugin-react from 7.17.0 to 7.18.3 dependencies javascript #46
• [Snyk] Upgrade @actions/github from 2.0.0 to 2.0.1 #45
• [Snyk] Upgrade @actions/exec from 1.0.2 to 1.0.3 #44
• Bump jest from 24.9.0 to 25.1.0 dependencies javascript #40
• Bump @actions/core from 1.2.0 to 1.2.2 dependencies javascript #39
• Bump @babel/preset-env from 7.7.7 to 7.8.4 dependencies javascript #38
• Bump eslint-plugin-unicorn from 14.0.1 to 16.0.0 dependencies javascript #37
• Bump @babel/cli from 7.7.5 to 7.8.4 dependencies javascript #36