fix(deps): add missing peer dependencies

[rtritto]

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• I agree to follow the code of conduct that this project follows, as appropriate.
• The changes are appropriately documented (if applicable).
• The changes have sufficient test coverage (if applicable).
• The testsuite passes successfully on my local machine (if applicable).

Summarize your changes:

Fix warnings:

➤ YN0002: │ @electron-forge/template-webpack-typescript@workspace:packages/template/webpack-typescript doesn't provide typescript (pd370b), requested by fork-ts-checker-webpack-plugin.
➤ YN0002: │ @electron-forge/template-webpack-typescript@workspace:packages/template/webpack-typescript doesn't provide webpack (p738c5), requested by fork-ts-checker-webpack-plugin.
➤ YN0002: │ electron-forge@workspace:. doesn't provide eslint-plugin-ava (pa3622), requested by @malept/eslint-config.

Changes

• @electron-forge/template-webpack-typescript dependency --> add typescript and webpack to dev dependencies of /packages/template/webpack-typescript/package.json
• electron-forge dependency --> add eslint-plugin-ava to dev dependencies of /package.json

[erickzhao]

I think this is an error with @malept/eslint-config because we don't use Ava as a test runner for Forge.

[rtritto]

So, in @malept/eslint-config, the eslint-plugin-ava peer dependency needs to became optional; I will open an issue.

Edit: I opened issue malept/eslint-config#107

[rtritto]

@erickzhao I removed eslint-plugin-ava from dev dependencies (in malept/eslint-config#107, it will be an optional peer dependency).
Please can you review for merge?