Release preparations for 10.0a3

Changelog update and versions bump

projects/firefox/config

@@ -8,7 +8,7 @@ git_submodule: 1
 gpg_keyring: torbutton.gpg
 
 var:
-  firefox_platform_version: 68.10.0
+  firefox_platform_version: 68.10.1
   firefox_version: '[% c("var/firefox_platform_version") %]esr'
   torbrowser_branch: 10.0
   branding_directory: '[% IF c("var/android") %]mobile/android[% ELSE %]browser[% END %]/branding/alpha'

projects/tor-browser/Bundle-Data/Docs/ChangeLog.txt

+Tor Browser 10.0a3 -- July 7 2020
+ * Android
+   * Update Firefox to 68.10.1esr
+
 Tor Browser 10.0a2 -- June 30 2020
  * All Platforms
    * Update Firefox to 68.10.0esr

rbm.conf

@@ -24,7 +24,7 @@ buildconf:
   git_signtag_opt: '-s'
 
 var:
-  torbrowser_version: '10.0a2'
+  torbrowser_version: '10.0a3'
   torbrowser_build: 'build1'
   torbrowser_incremental_from:
     - 10.0a1