Add conda to the list of requirements

If conda is not in the list of requirements, the scripts exit too early in case pyenv is not installed and the module is configured with:

 zstyle ':prezto:module:python' skip-virtualenvwrapper-init 'on' 
 zstyle ':prezto:module:python' conda-init 'on'

Tested on Amazon EC2 Linux for Deeplearning AMI 47.0 and MacOS 11.4

modules/python/init.zsh

@@ -44,7 +44,7 @@ fi
 unset local_pyenv
 
 # Return if requirements are not found.
-if (( ! $#commands[(i)python[23]#] && ! $+functions[pyenv] )); then
+if (( ! $#commands[(i)python[23]#] && ! $+functions[pyenv] && ! $+commands[conda] )); then
   return 1
 fi