chore: Migrate Windows Tests from Appveyor to CircleCI

.gitattributes

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DEPLOY.md

@@ -73,7 +73,7 @@ You can build the Cypress binary locally by running `yarn binary-build`. You can
 In order to publish a new `cypress` package to the npm registry, we must build and test it across multiple platforms and test projects. This makes publishing *directly* into the npm registry impossible. Instead, we have CI set up to do the following on every commit to `develop`:
 
 1. Build the npm package with the new target version baked in.
-2. Build the Linux/Mac binaries on CircleCI and build Windows on AppVeyor.
+2. Build the Linux, Mac & Windows binaries on CircleCI.
 3. Upload the binaries and the new npm package to `cdn.cypress.io` under the "beta" folder.
 4. Launch the test projects like [cypress-test-node-versions](https://github.com/cypress-io/cypress-test-node-versions) and [cypress-test-example-repos](https://github.com/cypress-io/cypress-test-example-repos) using the newly-uploaded package & binary instead of installing from the npm registry. That installation looks like this:
     ```shell