Downgrade @rollup/plugin-typescript to version 12.1.2 to fix failing builds

[filipsobol]

📌 Related issues

• Closes Fix failing CI caused by @rollup/plugin-typescript ckeditor5#18731.

[CKEditorBot]

🎉 Snyk checks have passed. No issues have been found so far.

✅ security/snyk check is complete. No issues have been found. (View Details)

✅ license/snyk check is complete. No issues have been found. (View Details)

✅ code/snyk check is complete. No issues have been found. (View Details)

[coveralls]

coverage: 86.688%. remained the same
when pulling 2a54f8e on ck/18731-downgrade-rollup-plugin-typescript
into eb21b77 on master.

[pomek]

• #master

   Exit code: 1
   Command: node ./scripts/postinstall.js
   Arguments:
   Directory: /home/pomek/Projects/ckeditor/ckeditor5/node_modules/ckeditor5-dev
   Output:
   > @ckeditor/[email protected] postinstall
   > node bin/postinstall.js
   
   Building: "@ckeditor/ckeditor5-dev-utils"...
   
   > @ckeditor/[email protected] build
   > rollup -c rollup.config.js
   
   
   src/index.ts, src/loaders/ck-debug-loader.ts → dist...
   [!] RollupError: src/loaders/getdebugloader.ts (6:9): "fileURLToPath" is not exported by "../../../../node_modules/url/url.js", imported by "src/loaders/getdebugloader.ts".
   https://rollupjs.org/troubleshooting/#error-name-is-not-exported-by-module
   src/loaders/getdebugloader.ts (6:9)
   4:  */
   5: import path from 'path';
   6: import { fileURLToPath } from 'url';
               ^
   7: const __filename = fileURLToPath(import.meta.url);
   8: const __dirname = path.dirname(__filename);
       at getRollupError (/home/pomek/Projects/ckeditor/ckeditor5/node_modules/rollup/dist/shared/parseAst.js:285:41)
       at Object.error (/home/pomek/Projects/ckeditor/ckeditor5/node_modules/rollup/dist/shared/parseAst.js:281:42)
       at Module.error (/home/pomek/Projects/ckeditor/ckeditor5/node_modules/rollup/dist/shared/rollup.js:18409:28)
       at Module.traceVariable (/home/pomek/Projects/ckeditor/ckeditor5/node_modules/rollup/dist/shared/rollup.js:18858:29)
       at ModuleScope.findVariable (/home/pomek/Projects/ckeditor/ckeditor5/node_modules/rollup/dist/shared/rollup.js:16518:39)
       at Identifier.bind (/home/pomek/Projects/ckeditor/ckeditor5/node_modules/rollup/dist/shared/rollup.js:9190:40)
       at CallExpression.bind (/home/pomek/Projects/ckeditor/ckeditor5/node_modules/rollup/dist/shared/rollup.js:6581:23)
       at CallExpression.bind (/home/pomek/Projects/ckeditor/ckeditor5/node_modules/rollup/dist/shared/rollup.js:13603:15)
       at VariableDeclarator.bind (/home/pomek/Projects/ckeditor/ckeditor5/node_modules/rollup/dist/shared/rollup.js:6581:23)
       at VariableDeclaration.bind (/home/pomek/Projects/ckeditor/ckeditor5/node_modules/rollup/dist/shared/rollup.js:6577:28)
  

• Changes from the PR:

   > @ckeditor/[email protected] postinstall
   > node bin/postinstall.js
   
   Building: "@ckeditor/ckeditor5-dev-utils"...
   
   > @ckeditor/[email protected] build
   > rollup -c rollup.config.js
   
   
   src/index.ts, src/loaders/ck-debug-loader.ts → dist...
   created dist in 1s
   Building: "@ckeditor/typedoc-plugins"...
   
   > @ckeditor/[email protected] build
   > rollup -c rollup.config.js
   
   
   src/index.ts → dist...
   created dist in 1.2s
   Building: "@ckeditor/ckeditor5-dev-web-crawler"...
   
   > @ckeditor/[email protected] build
   > rollup -c rollup.config.js
   
   
   src/index.ts → dist...
   created dist in 1.1s
   Building: "@ckeditor/ckeditor5-dev-changelog"...
   
   > @ckeditor/[email protected] build
   > rollup -c rollup.config.js
   
   
   src/index.ts → dist/index.js...
   created dist/index.js in 1.3s
   
   src/template.ts → dist/template.js...
   created dist/template.js in 927ms
   Building: "@ckeditor/ckeditor5-dev-build-tools"...
   
   > @ckeditor/[email protected] build
   > rollup -c rollup.config.js
  

[pomek]

LGTM.