Fix write certificate on first run command

[moritzraho]

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• I have signed the Adobe Open Source CLA.
• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• All new and existing tests passed.

[codecov]

Codecov Report

Merging #159 into master will decrease coverage by 0.18%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master     #159      +/-   ##
==========================================
- Coverage   93.63%   93.44%   -0.19%     
==========================================
  Files          18       18              
  Lines         534      534              
  Branches       67       67              
==========================================
- Hits          500      499       -1     
- Misses         30       31       +1     
  Partials        4        4

Impacted Files	Coverage Δ
src/commands/app/run.js	58.33% <100%> (-1.2%)	⬇️

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