fix: ignore SNOWPACK_PUBLIC_ env variable when generating __snowpack__/env.js

[gr2m]

Follow up to https://github.com/pikapkg/snowpack/pull/900\#discussion_r477058829 /cc @silverwind @FredKSchott

[vercel]

This pull request is being automatically deployed with Vercel (learn more).
To see the status of your deployment, click below or on the icon next to each commit.

🔍 Inspect: https://vercel.com/pikapkg/snowpack/4ale66yvb
✅ Preview: https://snowpack-git-900-follow-up-snowpack-public-env-variables-regex.pikapkg.vercel.app

[FredKSchott]

LGTM!

[gr2m]

I think the error on the Windows builds is legit. I tried to restart the build but it persists:

FAIL test/build/build.test.js (21.49 s)
  ● snowpack build › html-environment-variables

    Command failed with exit code 1: yarn testbuild
    'be' is not recognized as an internal or external command,
    operable program or batch file.
    events.js:174
          throw er; // Unhandled 'error' event
          ^

    Error: spawn be ENOENT

The testscript in package.json is

https://github.com/pikapkg/snowpack/pull/924/checks?check_run_id=1033570802#step:4:133

"cross-env SNOWPACK_PUBLIC_MY_ENV_VAR='my-var-replacement-configured-in-package.json' SNOWPACK_PUBLIC_='should be ignored' snowpack build"

I wonder if the "'be' is not recognized as an internal or external command" comes from the 'should be ignored' ` value? Any idea?

[FredKSchott]

ha! that's fascinating.

I don't know enough about cross-env, but i'd say just change it to 'ignoreme' or 'tobeignored' and call it a day :)

[FredKSchott]

Still LGTM, feel free to merge whenever you get tests passing :)