Bump versions up to 0.12.99 since a 0.12 release was just created.
diff --git a/RELEASE_CHECKLIST.txt b/RELEASE_CHECKLIST.txt
index 0bb2b77..e8702e6 100644
--- a/RELEASE_CHECKLIST.txt
+++ b/RELEASE_CHECKLIST.txt
@@ -18,7 +18,7 @@
 
 Update the version in json_c_version.h
 Update the version in Doxyfile
-Update the version in configure.in
+Update the version in configure.ac
 	Use ${release}.
 
 Update the libjson_la_LDFLAGS line in Makefile.am to the new version.
@@ -85,7 +85,7 @@
 Add new section to ChangeLog
 Update the version in json_c_version.h
 Update the version in Doxyfile
-Update the version in configure.in
+Update the version in configure.ac
     Use ${release}.99 to indicate a version "newer" than anything on the branch.
 
 Leave the libjson_la_LDFLAGS line in Makefile.am alone.