Prefer true/false to yes/no for Ansible booleans

This aligns the Ansible configuration with the changes made in
cisagov/skeleton-ansible-role#157.

src/aws.yml

@@ -1,7 +1,7 @@
 ---
 - hosts: all
   name: AWS-specific roles
-  become: yes
+  become: true
   become_method: ansible.builtin.sudo
   tasks:
     - name: Install Amazon EFS utilities

src/base.yml

@@ -1,7 +1,7 @@
 ---
 - hosts: all
   name: Setup base image
-  become: yes
+  become: true
   become_method: ansible.builtin.sudo
   tasks:
     - name: Install and configure automated security updates

src/example.yml

@@ -1,7 +1,7 @@
 ---
 - hosts: all
   name: Project-specific roles
-  become: yes
+  become: true
   become_method: ansible.builtin.sudo
   tasks:
     # The cisagov/ansible-role-example Ansible role is just a no-op,

src/python.yml

@@ -1,7 +1,7 @@
 ---
 - hosts: all
   name: Install pip3/python3 and remove pip2/python2
-  become: yes
+  become: true
   become_method: ansible.builtin.sudo
   tasks:
     # If pip were to be installed first, then the OS _could_ pull

src/upgrade.yml

@@ -1,7 +1,7 @@
 ---
 - hosts: all
   name: Upgrade base image
-  become: yes
+  become: true
   become_method: ansible.builtin.sudo
   tasks:
     - name: Upgrade all packages