Update rebar/enc binaries to R15B03-1

The recent release of Erlang 23.0 removed support for loading beam
modules compiled under R14 and earlier. Thus we're now forced to abandon
support for R13 and R14.
diff --git a/.gitignore b/.gitignore
index c6154b9..d281c7b 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,5 +1,6 @@
 .eunit
 .rebar
+.tool-versions
 .jiffy.dev
 *.app
 *.beam
diff --git a/enc b/enc
index 3626e16..5338498 100755
--- a/enc
+++ b/enc
Binary files differ
diff --git a/rebar b/rebar
index 36ef011..b3eaa8e 100755
--- a/rebar
+++ b/rebar
Binary files differ