use python3 for ansible

tests/Vagrantfile

@@ -10,6 +10,7 @@ Vagrant.configure("2") do |config|
 
     pip.vm.provision "ansible" do |ansible|
       ansible.playbook = "test-pip.yml"
+      ansible.extra_vars = { ansible_python_interpreter:"/usr/bin/python3" }
     end
   end
   config.vm.define "docker" do |docker| 
@@ -20,6 +21,7 @@ Vagrant.configure("2") do |config|
 
     docker.vm.provision "ansible" do |ansible|
       ansible.playbook = "test-docker.yml"
+      ansible.extra_vars = { ansible_python_interpreter:"/usr/bin/python3" }
     end
   end
 end

tests/test-docker.yml

@@ -26,8 +26,10 @@
     matrix_synapse_supervision_method: docker
   roles:
     - role: geerlingguy.pip
+      pip_package: python3-pip
       pip_install_packages:
         - name: docker
+        - name: psycopg2-binary
     - role: geerlingguy.docker
     - role: geerlingguy.postgresql
       postgresql_databases:

tests/test-pip.yml

@@ -24,6 +24,9 @@
       when: matrix_synapse_version != "v"~(api_version.content | from_json).server.version
   roles:
     - role: geerlingguy.pip
+      pip_package: python3-pip
+      pip_install_packages:
+        - name: psycopg2-binary
     - role: geerlingguy.postgresql
       postgresql_databases:
         - name: "{{ dbname }}"