title: Upgrading pip for different versions of python
body: <p>I have two versions of python installed on my computer (3.6 and 3.7).  Just upgraded pip to the latest version (19.0.1) using the command <code>python -m pip install --upgrade pip</code> however i think it only upgraded the pip for python version 3.6.  When attempting to install a package specifically for python version 3.7 with the following command <code>pip3.7 install scipy</code> i got the message saying <code>You are using pip version 18.1, however version 19.0.1 is available.</code> Clearly only the pip for version 3.6 was upgraded.  I cannot figure out a command to upgrade 3.7 pip as well.  I tried the following:</p>
  
  <pre><code>python -m pip3.7 install --upgrade pip
  </code></pre>
  
  <p>This did not work (Trying to use the logic of how packages are handled for different versions of python).  Could not find a question that addressed this specific issue.  Any help would be greatly appreciated. </p>