build: update some packages in dockerfiles

Ubuntu no longer serves old version

contrib/build-linux/appimage/Dockerfile

@@ -4,7 +4,7 @@ ENV LC_ALL=C.UTF-8 LANG=C.UTF-8
 
 RUN apt-get update -q && \
     apt-get install -qy \
-        git=1:2.7.4-0ubuntu1.6 \
+        git=1:2.7.4-0ubuntu1.7 \
         wget=1.17.1-1ubuntu1.5 \
         make=4.1-6 \
         autotools-dev=20150820.1 \

contrib/build-wine/Dockerfile

@@ -13,7 +13,7 @@ RUN dpkg --add-architecture i386 && \
 
 RUN apt-get update -q && \
         apt-get install -qy \
-        git=1:2.17.1-1ubuntu0.4 \
+        git=1:2.17.1-1ubuntu0.5 \
         p7zip-full=16.02+dfsg-6 \
         make=4.1-9.1ubuntu1 \
         mingw-w64=5.0.3-1 \