Use ember-modifier v3 API

[tcjr]

This PR updates the class-based modifiers to use the ember-modifier v3 API.

In summary

• The lifecycle hooks didInstall, didReceiveArguments, didUpdateArguments have all been replaced with a single modify hook. This hook gets called on initial install and whenever the args change.
• The Modify base class no longer provides this.element. Instead, element is provided in the modify hook, so the modifier implementation sets this.element there.
• The Modify base class no longer provides this.args. Instead, positional and named args are passed to the modify hook. I updated the implementation to set this._namedArgs and this._positionalArgs so the rest of the code can use those where it used to use this.args.named and this.args.positional respectively.
• The willDestroy hook has been removed. Instead, the implementation registers a cleanup function in the modifier's constructor using @ember/destroyable. I moved the code that was in the willDestroy hook into this cleanup function.

I updated the ember-try scenarios and ci to include the last two LTS versions (4.4 and 4.8).

I also updated the package.json to drop ^2.0.0 from the ember-modifier dependency. I guess this means if you merge this, it's a breaking change so maybe you'll need to bump the major version.

Fixes #4

[donaldsonjulia]

Would love if this could be merged. At this point we cannot continue to use ember-tippy in our project because of the ember-modifier deprecations. The changes made in this PR fix the functionality.

[nag5000]

@tcjr The changes of package-lock.json and .npmrc seems are not really related to this PR, could you exclude it from the changes?

I no longer follow the ember-modifier changes and the ember ecosystem in general, but I believe I can merge it and release it as a beta version. Thank you!

[tcjr]

@nag5000 I removed the .npmrc and instead updated the ember-try config. I also updated the CI workflow since github wants us to use Node 16 in actions.

These should all pass now. https://github.com/nag5000/ember-tippy/actions/runs/4226303928