Fix YAML quotes (brisbanesocialchess#671)

Author: jbampton

frontend/meetups/saturday.md

@@ -7,9 +7,9 @@ hosts:
   - Ben Martin
   - Peiqi Sun
 hosts_images:
-  - src: /assets/avatars/octoman.png
+  - src: '/assets/avatars/octoman.png'
     alt: Ben Martin
-  - src: /assets/avatars/octoman.png
+  - src: '/assets/avatars/octoman.png'
     alt: Peiqi Sun
 description: |
   Calling all Blunderers! Join Brisbane's coolest chess crew every Saturday morning as we transform West End Park Café into checkered board central.<br/>

frontend/meetups/sunday.md

@@ -8,11 +8,11 @@ hosts:
   - Matt McLean
   - Steve Anderson
 hosts_images:
-  - src: /assets/avatars/octoman.png
+  - src: '/assets/avatars/octoman.png'
     alt: Joseph Tan
-  - src: /assets/avatars/matt.jpeg
+  - src: '/assets/avatars/matt.jpeg'
     alt: Matt McLean
-  - src: /assets/avatars/octoman.png
+  - src: '/assets/avatars/octoman.png'
     alt: Steve Anderson
 description: |
   Calling all Blunderers near and far - Sundays are our day to plot, move and laugh. <br />