Let pip upgrade packages

Since we now longer pin versions to the patch version, we should make
an install cause the packages upgrade within the version constraints
rathern than just settle for the current version if it is already
installed.

tljh/installer.py

@@ -124,9 +124,7 @@ def ensure_jupyterhub_package(prefix):
         'libcurl4-openssl-dev',
         'build-essential'
     ])
-    conda.ensure_pip_packages(prefix, [
-        'pycurl==7.*'
-    ])
+    conda.ensure_pip_packages(prefix, ['pycurl==7.*'], upgrade=True)
 
     conda.ensure_pip_packages(
         prefix,
@@ -141,6 +139,7 @@ def ensure_jupyterhub_package(prefix):
             "jupyterhub-idle-culler==1.*",
             "git+https://github.com/yuvipanda/jupyterhub-configurator@317759e17c8e48de1b1352b836dac2a230536dba"
         ],
+        upgrade=True,
     )
     traefik.ensure_traefik_binary(prefix)
 
@@ -193,20 +192,28 @@ def ensure_user_environment(user_requirements_txt_file):
             conda.install_miniconda(installer_path, USER_ENV_PREFIX)
         conda_version = '4.10.3'
 
-    conda.ensure_conda_packages(USER_ENV_PREFIX, [
-        # Conda's latest version is on conda much more so than on PyPI.
-        'conda==' + conda_version,
-        'mamba==' + mambaforge_mamba_version,
-    ])
+    conda.ensure_conda_packages(
+        USER_ENV_PREFIX,
+        [
+            # Conda's latest version is on conda much more so than on PyPI.
+            'conda==' + conda_version,
+            'mamba==' + mambaforge_mamba_version,
+        ],
+    )
 
     conda.ensure_pip_requirements(
         USER_ENV_PREFIX,
         os.path.join(HERE, 'requirements-base.txt'),
+        upgrade=True,
     )
 
     if user_requirements_txt_file:
         # FIXME: This currently fails hard, should fail soft and not abort installer
-        conda.ensure_pip_requirements(USER_ENV_PREFIX, user_requirements_txt_file)
+        conda.ensure_pip_requirements(
+            USER_ENV_PREFIX,
+            user_requirements_txt_file,
+            upgrade=True,
+        )
 
 
 def ensure_admins(admin_password_list):
@@ -313,7 +320,7 @@ def setup_plugins(plugins=None):
     """
     # Install plugins
     if plugins:
-        conda.ensure_pip_packages(HUB_ENV_PREFIX, plugins)
+        conda.ensure_pip_packages(HUB_ENV_PREFIX, plugins, upgrade=True)
 
     # Set up plugin infrastructure
     pm = pluggy.PluginManager('tljh')
@@ -342,7 +349,11 @@ def run_plugin_actions(plugin_manager):
         logger.info('Installing {} hub pip packages collected from plugins: {}'.format(
             len(hub_pip_packages), ' '.join(hub_pip_packages)
         ))
-        conda.ensure_pip_packages(HUB_ENV_PREFIX, hub_pip_packages)
+        conda.ensure_pip_packages(
+            HUB_ENV_PREFIX,
+            hub_pip_packages,
+            upgrade=True,
+        )
 
     # Install conda packages
     conda_packages = list(set(itertools.chain(*hook.tljh_extra_user_conda_packages())))
@@ -358,7 +369,11 @@ def run_plugin_actions(plugin_manager):
         logger.info('Installing {} user pip packages collected from plugins: {}'.format(
             len(user_pip_packages), ' '.join(user_pip_packages)
         ))
-        conda.ensure_pip_packages(USER_ENV_PREFIX, user_pip_packages)
+        conda.ensure_pip_packages(
+            USER_ENV_PREFIX,
+            user_pip_packages,
+            upgrade=True,
+        )
 
     # Custom post install actions
     hook.tljh_post_install()