Fix schema violations in custom task environments

As reported by ansible-lint 6.2.1:

schema: [{'PYTHONPATH': '.'}] is not of type 'object' (schema[tasks])
roles/aurweb/tasks/main.yml:1

schema: [{'SHELL': '/bin/bash'}] is not of type 'object' (schema[tasks])
roles/dbscripts/tasks/main.yml:1

roles/aurweb/tasks/main.yml

@@ -137,7 +137,7 @@
   args:
     chdir: "{{ aurweb_dir }}"
   environment:
-    - PYTHONPATH: .
+    PYTHONPATH: .
   become: true
   become_user: "{{ aurweb_user }}"
   when: release.changed or db_created.changed

roles/dbscripts/tasks/main.yml

@@ -284,7 +284,7 @@
 - name: configure svntogit pull upstream branch
   command: git pull --set-upstream public master chdir=/srv/svntogit/repos/{{ item }}
   environment:
-    - SHELL: /bin/bash
+    SHELL: /bin/bash
   with_items:
     - community
     - packages