fix: use @urql/core instead of urql to not pull react

[stefanmaric]

After #338 the extension fails to load on workspaces without react installed.

react is imported by the bundled urql package.

Using the @urql/core package instead solves the issue.

Closes #345

[linux-foundation-easycla[bot]]

The committers are authorized under a signed CLA.

• :white_check_mark: Stefan Maric (20cc1f22e4223c62097ff1278dab4208d0d94e80)

[acao]

thank you!