Increasing API version to 8

Needed because of recent changes to Diagnostic struct etc.

cpp/ycm/versioning.cpp

@@ -20,7 +20,7 @@ namespace YouCompleteMe {
 int YcmCoreVersion() {
   // We increment this every time when we want to force users to recompile
   // ycm_core.
-  return 7;
+  return 8;
 }
 
 }  // namespace YouCompleteMe

python/ycm/base.py

@@ -187,7 +187,7 @@ def OverlapLength( left_string, right_string ):
       length += 1
 
 
-COMPATIBLE_WITH_CORE_VERSION = 7
+COMPATIBLE_WITH_CORE_VERSION = 8
 
 def CompatibleWithYcmCore():
   try: