thunderbird: Update version from 45.4.0 to 45.5.0

Release notes [1]:

> Version 45.5.0, first offered to Release channel users on November 18,
> 2016
>
> ## What’s New ##
>
> *   Changed: IMPORTANT: Changed recipient address entry: Arrow-keys now
> copy the pop-up value to the input field. Mouse-hovered pop-up value
> can no longer be confirmed with tab or enter key. This restores the
> behavior of Thunderbird 24.
> *   Changed: Support changes to character limit in Twitter
> *   Fixed: Reply with selected text containing quote resulted in wrong
> quoting level indication
> *   Fixed: Mail address display at header pane displayed incorrectly
> if the address contains UTF-8 according to RFC 6532
> *   Fixed: Attempting to sort messages on the Date field whilst a
> quick filter is applied got stuck on sort descending
> *   Fixed: Email invitation might not be displayed when description
> contains non-ASCII characters

[1] https://www.mozilla.org/en-US/thunderbird/45.5.0/releasenotes/

thunderbird.be0

@@ -2,7 +2,7 @@
 
 #export BEE_TMP_TMPDIR=/dev/shm BEE_TMP_BUILDROOT=/dev/shm/bee-root BEE_MAKEFLAGS='-j80'
 
-# BEE_VERSION thunderbird-45.4.0-0
+# BEE_VERSION thunderbird-45.5.0-0
 
 SRCURL[0]="https://ftp.mozilla.org/pub/thunderbird/releases/${PKGVERSION}/source/thunderbird-${PKGVERSION}.source.tar.xz"