FindBin: Update $VERSION

Per incline comments in Porting/Maintainers.PL:

(For dist/ distributions, which are blead-first, a request should be
placed with the releaser(s) to upload the corresponding cpan release,
and the entry in this file should only be updated when that release has
been done.)

FindBin-1.54 has been released on CPAN, so now we can update $VERSION in
core to keep Porting/core-cpan-diff -ax happy.

Porting/Maintainers.pl

@@ -607,7 +607,7 @@ package Maintainers;
     },
 
     'FindBin' => {
-        'DISTRIBUTION' => 'TODDR/FindBin-1.53.tar.gz',
+        'DISTRIBUTION' => 'TODDR/FindBin-1.54.tar.gz',
         'FILES'        => q[dist/FindBin],
     },