Pin integer-encoding to 3.0.3 (#2627)

diff --git a/lib/rs/Cargo.toml b/lib/rs/Cargo.toml
index 0b19740..292f1bb 100644
--- a/lib/rs/Cargo.toml
+++ b/lib/rs/Cargo.toml
@@ -14,7 +14,7 @@
 
 [dependencies]
 byteorder = "1.3"
-integer-encoding = "3.0"
+integer-encoding = "3.0.3"
 log = {version = "0.4", optional = true}
 ordered-float = "2.0"
 threadpool = {version = "1.7", optional = true}