configure.ac: version bump for RC4

Signed-off-by: Philip Tricca <philip.b.tricca@intel.com>
diff --git a/configure.ac b/configure.ac
index 48a303b..9614780 100644
--- a/configure.ac
+++ b/configure.ac
@@ -26,7 +26,7 @@
 # THE POSSIBILITY OF SUCH DAMAGE.
 #;**********************************************************************;
 AC_INIT([tpm2-tss],
-        [2.0.0_rc3],
+        [2.0.0_rc4],
         [https://github.com/tpm2-software/tpm2-tss/issues],
         [],
         [https://github.com/tpm2-software/tpm2-tss])