use discovered python version to set pip version

tasks/install.yml

@@ -1,5 +1,5 @@
 ---
-- block: 
+- block:
     - name: Install dependencies
       package:
         name: "{{ item }}"
@@ -15,7 +15,7 @@
     - name: Install python packages
       pip:
         name: "{{ item.name }}"
-        executable: "{{ item.exec | default('/usr/bin/pip3') }}"
+        executable: "{{ item.exec | default('/usr/bin/pip' + ansible_python.version.major) }}"
         state: present
       loop: "{{ dockerengine_packages_python }}"
       loop_control: