message: Ask caches to always revalidate before using cached service worker / html
diff: @@ -971,7 +971,8 @@ AddEncoding br .br
  <FilesMatch "service-worker\.js(\.(gz|br))?">
  <IfModule mod_headers.c>
  - Header set Cache-Control "max-age=0, s-maxage=86400"
  + # no-cache = revalidate with the server before using
  + Header set Cache-Control "max-age=0, s-maxage=86400, must-revalidate"
  Header unset Expires
  </IfModule>
  </FilesMatch>
  @@ -980,7 +981,7 @@ AddEncoding br .br
  <FilesMatch "\.html(\.(gz|br))?">
  <IfModule mod_headers.c>
  - Header set Cache-Control "max-age=0, s-maxage=86400"
  + Header set Cache-Control "max-age=0, s-maxage=86400, must-revalidate"
  Header unset Expires
  </IfModule>
  </FilesMatch>
  @@ -989,7 +990,7 @@ AddEncoding br .br
  <FilesMatch "version\.json(\.(gz|br))?">
  <IfModule mod_headers.c>
  - Header set Cache-Control "max-age=900, s-maxage=86400"
  + Header set Cache-Control "max-age=900, s-maxage=86400, must-revalidate"
  Header unset Expires
  </IfModule>
  </FilesMatch>
  