[alembic] update to 1.7.8

ports/alembic/CONTROL

@@ -1,4 +1,4 @@
 Source: alembic
-Version: 1.7.7
+Version: 1.7.8
 Build-Depends: ilmbase, hdf5
 Description: Alembic is an open framework for storing and sharing scene data that includes a C++ library, a file format, and client plugins and applications. http://alembic.io/

ports/alembic/portfile.cmake

@@ -8,8 +8,8 @@ endif()
 vcpkg_from_github(
     OUT_SOURCE_PATH SOURCE_PATH
     REPO alembic/alembic
-    REF 1.7.7
-    SHA512 0ebcf6b9304e84bc60f1c146d0b5e5c5b1de43974ec0725293c444b48b22640945f5883eb9afd46c1ac9f0c260d6f22ff29b4866d6525c416339877be984b149
+    REF 1.7.8
+    SHA512 bc36e30d1aecd67da16247365a973c462e9716309d090fefe36f625c8d2ab2d517fe8ac694a9188cd6eeb623a3217f59f461c82fcfec43d0a60a07381526983a
     HEAD_REF master
 )