title: How to solve Python poetry dependency error
body: <p>When trying to install the Python dependencies with Poetry, I've the following error:</p>
  
  <pre><code>$ poetry install                                                                                                    
  The currently activated Python version 2.7.15 is not supported by the project (&gt;=3.6).
  Trying to find and use a compatible version.
  Using python3 (3.7.4)
  Skipping virtualenv creation, as specified in config file.
  Updating dependencies
  Resolving dependencies... (1.7s)
  
  [SolverProblemError]
  The current project's Python requirement (&gt;=3.6) is not compatible with some of the required packages Python requirement:
    - pre-commit requires Python &gt;=3.6.1
  
  Because no versions of pre-commit match &gt;2.2.0,&lt;3.0.0
   and pre-commit (2.2.0) requires Python &gt;=3.6.1, pre-commit is forbidden.
  So, because my-proj depends on pre-commit (^2.2.0), version solving failed.
  </code></pre>
  
  <p>Here is my environment:</p>
  
  <pre><code>$ python3 --version                                                                                                 
  Python 3.7.4
  $ poetry --version                                                                                                  
  Poetry version 1.0.5
  $ pre-commit --version                                                                                             
  pre-commit 2.2.0
  </code></pre>
  
  <p>And a sample of my pyproject.toml:</p>
  
  <pre><code>...
  [tool.poetry.dependencies]
  python = "&gt;=3.6"
  ...
  
  [tool.poetry.dev-dependencies]
  pre-commit = "^2.2.0"
  ...
  </code></pre>
  
  <p>I've tried changing the python version in pyproject to 3.7, but didn't change the result. And if I remove the pre-commit dependency, I've got the same error on another dependency.</p>
  
  <p>I don't know what should I look for: upgrading/downgrading the versions, incompatible versions</p>