update to the latest Qt + sync CHANGELOG

CHANGELOG.md

@@ -1,6 +1,7 @@
 v0.12.6 (unreleased)
 --------------------
 * **#3953**: fix TOC and other special pages not present in output PDF (#3962)
+* **#3242**: **[qt]** fix regression from #2353 in setLineDash for Canvas (qt#35)
 
 v0.12.5 (2018-06-11)
 --------------------

qt

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-Subproject commit 5db36ec76b29712eb2c5bd0625c2c77d7468b3fc
+Subproject commit 5e3cf6b23dd9a0fc042e890b31c62fff6927e0ff