Update publish job with pypi api tokens (#262)

## Problem

Now that PyPI has required 2FA for all accounts, we have to publish
using API Tokens instead of username and password.

## Solution

- Update workflows with pypi api token.
- Delete unused jobs that publish to testpypi

## Type of Change

- [x] Infrastructure change (CI configs, etc)

## Test Plan

Describe specific steps for validating this change.

.github/workflows/alpha-release.yaml

@@ -38,5 +38,5 @@ jobs:
       prereleaseSuffix: ${{ inputs.prereleaseSuffix }}
       TWINE_REPOSITORY: 'pypi'
     secrets:
-      PYPI_USERNAME: ${{ secrets.PROD_PYPI_USERNAME }}
-      PYPI_PASSWORD: ${{ secrets.PROD_PYPI_PASSWORD }}
+      PYPI_USERNAME: __token__
+      PYPI_PASSWORD: ${{ secrets.PROD_PYPI_PUBLISH_TOKEN }}

.github/workflows/nightly-release.yaml

@@ -60,6 +60,6 @@ jobs:
         id: pypi_upload
         env:
           TWINE_REPOSITORY: pypi
-          PYPI_USERNAME: ${{ secrets.PROD_PYPI_USERNAME }}
-          PYPI_PASSWORD: ${{ secrets.PROD_PYPI_PASSWORD }}
+          PYPI_USERNAME: __token__
+          PYPI_PASSWORD: ${{ secrets.PROD_PYPI_PUBLISH_TOKEN }}
         run: make upload

.github/workflows/release.yaml

@@ -18,10 +18,6 @@ on:
           - 'minor' # new features, backwards compatible
           - 'major' # breaking changes
 
-env:
-  PYPI_USERNAME: ${{ secrets.TEST_PYPI_USERNAME }}
-  PYPI_PASSWORD: ${{ secrets.TEST_PYPI_PASSWORD }}
-
 jobs:
   testing:
     uses: './.github/workflows/testing.yaml'
@@ -37,5 +33,5 @@ jobs:
       TWINE_REPOSITORY: 'pypi'
       prereleaseSuffix: ''
     secrets:
-      PYPI_USERNAME: ${{ secrets.PROD_PYPI_USERNAME }}
-      PYPI_PASSWORD: ${{ secrets.PROD_PYPI_PASSWORD }}
+      PYPI_USERNAME: __token__
+      PYPI_PASSWORD: ${{ secrets.PROD_PYPI_PUBLISH_TOKEN }}