fix: Add missing env var for GitHub Actions

[nicholas-codecov]

Description

This PR includes the changes of #184, while also including a changeset.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 79.12%. Comparing base (168610b) to head (85c628d).
Report is 1 commits behind head on main.

✅ All tests successful. No failed tests found.

Additional details and impacted files

Components	Coverage Δ
Plugin core	97.07% <100.00%> (+<0.01%)	⬆️
Rollup plugin	10.81% <ø> (ø)
Vite plugin	11.02% <ø> (ø)
Webpack plugin	49.88% <ø> (ø)

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[codecov-notifications]

Codecov Report

All modified and coverable lines are covered by tests ✅

✅ All tests successful. No failed tests found.

Components	Coverage Δ
Plugin core	97.07% <100.00%> (+<0.01%)	⬆️
Rollup plugin	10.81% <ø> (ø)
Vite plugin	11.02% <ø> (ø)
Webpack plugin	49.88% <ø> (ø)

📢 Thoughts on this report? Let us know!

[codecov]

Bundle Report

Changes will decrease total bundle size by 41.35kB (-0.71%) ⬇️. This is within the configured threshold ✅

Detailed changes

Bundle name	Size	Change
@codecov/bundler-plugin-core-cjs	59.17kB	13 bytes (0.02%) ⬆️
@codecov/bundler-plugin-core-esm	12.29kB	40.97kB (-76.93%) ⬇️
@codecov/nuxt-plugin-esm	830 bytes	397 bytes (-32.36%) ⬇️
@codecov/example-sveltekit-app-client-esm	714.98kB	2 bytes (0.0%) ⬆️
@codecov/example-sveltekit-app-server-esm	974.85kB	1 bytes (0.0%) ⬆️

[codecov-staging]

Bundle Report

Changes will increase total bundle size by 1.08kB (0.04%) ⬆️. This is within the configured threshold ✅

Detailed changes

Bundle name	Size	Change
@codecov/bundler-plugin-core-cjs	59.17kB	13 bytes (0.02%) ⬆️
@codecov/rollup-plugin-esm	2.32kB	1.02kB (78.42%) ⬆️
@codecov/sveltekit-plugin-esm	1.09kB	198 bytes (22.22%) ⬆️
@codecov/solidstart-plugin-esm	949 bytes	142 bytes (-13.02%) ⬇️
@codecov/webpack-plugin-esm	3.36kB	6 bytes (-0.18%) ⬇️