Bump version to 10.3.4.1 and update Changes

Author: ivanimanishi

Changes

@@ -1,3 +1,11 @@
+10.3.4.1 (relative to 10.3.4.0)
+========
+
+Build
+-----
+
+- IECoreUSD : Support for USD 20.??
+
 10.3.4.0 (relative to 10.3.3.0)
 ========
 

SConstruct

@@ -57,7 +57,7 @@ SConsignFile()
 ieCoreMilestoneVersion = 10 # for announcing major milestones - may contain all of the below
 ieCoreMajorVersion = 3 # backwards-incompatible changes
 ieCoreMinorVersion = 4 # new backwards-compatible features
-ieCorePatchVersion = 0 # bug fixes
+ieCorePatchVersion = 1 # bug fixes
 ieCoreVersionSuffix = "" # used for alpha/beta releases. Example: "a1", "b2", etc.
 
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