Cannot link ESM plugins into CJS plugins

[mdonnalley]

Describe the bug

You are not able to install or link ESM plugins into a CJS CLI

Actual Behavior

~/code/esm-cli » ~/code/node14-cli/bin/dev plugins link
Linking plugin ....
(node:66140) [ERR_UNKNOWN_FILE_EXTENSION] TypeError Plugin: esm-cli [ERR_UNKNOWN_FILE_EXTENSION]: Unknown file extension ".ts" for /Users/mdonnalley/code/esm-cli/src/commands/test.ts
module: @oclif/core@2.9.4
task: toCached
plugin: esm-cli
root: /Users/mdonnalley/code/esm-cli
See more details with DEBUG=*
(Use `node --trace-warnings ...` to show where the warning was created)
(node:66140) [ERR_UNKNOWN_FILE_EXTENSION] TypeError Plugin: esm-cli [ERR_UNKNOWN_FILE_EXTENSION]: Unknown file extension ".ts" for /Users/mdonnalley/code/esm-cli/src/commands/hello/index.ts
module: @oclif/core@2.9.4
task: toCached
plugin: esm-cli
root: /Users/mdonnalley/code/esm-cli
See more details with DEBUG=*
(node:66140) [ERR_UNKNOWN_FILE_EXTENSION] TypeError Plugin: esm-cli [ERR_UNKNOWN_FILE_EXTENSION]: Unknown file extension ".ts" for /Users/mdonnalley/code/esm-cli/src/commands/hello/world.ts
module: @oclif/core@2.9.4
task: toCached
plugin: esm-cli
root: /Users/mdonnalley/code/esm-cli
node14-cli: linking plugin esm-cli... done

Expected Behavior

No errors when linking ESM plugin to CJS plugin

[git2gus]

This issue has been linked to a new work item: W-13831264

[mdonnalley]

After deliberation with the team, we've decided that we are not going to support linking ESM plugins into CJS plugins. It's important to note that this only applies to linking plugins. Installing plugins in a production environment currently works and will continue to be supported.