[C3] fix: use a valid compatibility date for worker templates

[petebacondarwin]

Fixes #2385

What this PR solves / how to test:

Previously, we changed wrangler.toml to use the current date for the compatibility_date setting in wrangler.toml when generating workers. But this is almost always going to be new recent and results in a warning.

Now we look up the most recent compatibility date via npm on the workerd package and use that instead.

To test, build the create-cloudflare-package and then use it to build a workers project.
Check that the output displays:

├ Retrieving current workerd compatibility date 
│ compatibility date 2023-05-18

And that the generated wrangler.toml contains this date:

compatibility_date = "2023-05-18"

Associated docs issue(s)/PR(s):

• N/A

Author has included the following, where applicable:

• Tests
• Changeset (Changeset guidelines)

Reviewer is to perform the following, as applicable:

• Checked for inclusion of relevant tests
• Checked for inclusion of a relevant changeset
• Checked for creation of associated docs updates
• Manually pulled down the changes and spot-tested

[changeset-bot]

🦋 Changeset detected

Latest commit: 1073898

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
create-cloudflare	Patch

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[github-actions]

A wrangler prerelease is available for testing. You can install this latest build in your project with:

npm install --save-dev https://prerelease-registry.devprod.cloudflare.dev/workers-sdk/runs/5356761586/npm-package-wrangler-3343

You can reference the automatically updated head of this PR with:

npm install --save-dev https://prerelease-registry.devprod.cloudflare.dev/workers-sdk/prs/3343/npm-package-wrangler-3343

Or you can use npx with this latest build directly:

npx https://prerelease-registry.devprod.cloudflare.dev/workers-sdk/runs/5356761586/npm-package-wrangler-3343 dev path/to/script.js

Additional artifacts:

npm install https://prerelease-registry.devprod.cloudflare.dev/workers-sdk/runs/5356761586/npm-package-cloudflare-pages-shared-3343

Note that these links will no longer work once the GitHub Actions artifact expires.

[codecov]

Codecov Report

Merging #3343 (eab3088) into main (9ae3d93) will increase coverage by 0.02%.
The diff coverage is n/a.

❗ Current head eab3088 differs from pull request most recent head 1073898. Consider uploading reports for the commit 1073898 to get more accurate results

@@            Coverage Diff             @@
##             main    #3343      +/-   ##
==========================================
+ Coverage   75.07%   75.10%   +0.02%     
==========================================
  Files         183      183              
  Lines       11083    11083              
  Branches     2917     2917              
==========================================
+ Hits         8321     8324       +3     
+ Misses       2762     2759       -3     

see 2 files with indirect coverage changes

[rozenmd]

Looks good to me, I'd probably wait for a review from someone more familiar with C3 though.

[petebacondarwin]

OK I have rebased and I think I have addressed all the comments.
My slight worry is that the type parameters are a bit messed up. But it works as is right now. We can probably be more sophisticated later?

[mrbbot]

Looks good! One minor comment, then I'll approve. 🙂