Correcting a typo in the Asciidoctor 1.5.0 release announcement

Changed:
"Asciidoctor would not be what it is today with her dedication"
to:
"Asciidoctor would not be what it is today without her dedication"
Merge pull request #295 from bleathem/patch-1

Correcting a typo in the Asciidoctor 1.5.0 release announcement