Fix compilation for non-modules

[vearutop]

Description

This PR adds a check for GO111MODULE env var to avoid go mod tidy in non-module mode.

Motivation & context

Relates to #405.

Type of change

• Bug fix (non-breaking change which fixes an issue)

Note to other contributors

No note.

Update required of cucumber.io/docs

No update.

Checklist:

• I have read the CONTRIBUTING document.
• My code follows the code style of this project.
• I have added tests to cover my changes.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have added an entry to the "Unreleased" section of the CHANGELOG, linking to this pull request.

[codecov]

Codecov Report

Merging #436 (d6eac09) into main (239a424) will increase coverage by 0.00%.
The diff coverage is 50.00%.

@@           Coverage Diff           @@
##             main     #436   +/-   ##
=======================================
  Coverage   81.57%   81.58%           
=======================================
  Files          26       26           
  Lines        2176     2177    +1     
=======================================
+ Hits         1775     1776    +1     
  Misses        308      308           
  Partials       93       93           

Impacted Files	Coverage Δ
internal/builder/builder.go	54.87% <50.00%> (+0.23%)	⬆️

---

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 239a424...d6eac09. Read the comment docs.