Add test proto file

Author: AdrienVannson

tests/inputs/validation/validation.proto

@@ -0,0 +1,20 @@
+syntax = "proto3";
+
+package validation;
+
+message Message {
+    int32 int32_value = 1;
+    int64 int64_value = 2;
+    uint32 uint32_value = 3;
+    uint64 uint64_value = 4;
+    sint32 sint32_value = 5;
+    sint64 sint64_value = 6;
+    fixed32 fixed32_value = 7;
+    fixed64 fixed64_value = 8;
+    sfixed32 sfixed32_value = 9;
+    sfixed64 sfixed64_value = 10;
+
+    float float_value = 11;
+
+    string string_value = 12;
+}