Don't build new environments for package and vendoring'

Signed-off-by: Dan Ryan <dan@danryan.co>

.azure-pipelines/steps/build-package.yml

@@ -1,20 +1,3 @@
-steps:
-- task: UsePythonVersion@0
-  inputs:
-    versionSpec: $(python.version)
-    architecture: '$(python.architecture)'
-    addToPath: true
-  displayName: Use Python $(python.version)
-
-- template: install-dependencies.yml
-
-- script: |
-    echo '##vso[task.setvariable variable=PIPENV_DEFAULT_PYTHON_VERSION]$(PYTHON_VERSION)'
-  env:
-    PYTHON_VERSION: $(python.version)
-
-- template: create-virtualenv.yml
-
 - script: |
     python -m pip install --upgrade wheel pip setuptools twine readme_renderer[md]
     python setup.py sdist bdist_wheel

.azure-pipelines/steps/run-vendor-scripts.yml

@@ -1,20 +1,3 @@
-steps:
-- task: UsePythonVersion@0
-  inputs:
-    versionSpec: $(python.version)
-    architecture: '$(python.architecture)'
-    addToPath: true
-  displayName: Use Python $(python.version)
-
-- template: install-dependencies.yml
-
-- script: |
-    echo '##vso[task.setvariable variable=PIPENV_DEFAULT_PYTHON_VERSION]$(PYTHON_VERSION)'
-  env:
-    PYTHON_VERSION: $(python.version)
-
-- template: create-virtualenv.yml
-
 - script: |
     python -m pip install --upgrade invoke requests parver bs4 vistir towncrier pip setuptools wheel --upgrade-strategy=eager
     python -m invoke vendoring.update