Use docopt-cpp from Buildroot upstream

Change-Id: If76dd0d71fe38b530493e3252293e6522520dbd0
diff --git a/.zuul.yaml b/.zuul.yaml
index bdede81..8355f52 100644
--- a/.zuul.yaml
+++ b/.zuul.yaml
@@ -23,7 +23,6 @@
       - github/CESNET/libnetconf2
       - github/CESNET/Netopeer2
       - github/onqtam/doctest
-      - github/docopt/docopt.cpp
       - github/rollbear/trompeloeil
       - github/tplgy/cppcodec
       - github/AmokHuginnsson/replxx
diff --git a/ci/build.sh b/ci/build.sh
index 14e73bb..14b7055 100755
--- a/ci/build.sh
+++ b/ci/build.sh
@@ -76,7 +76,7 @@
     for PROJECT in \
             libyang sysrepo libnetconf2 netopeer2 \
             libyang-cpp sysrepo-cpp \
-            docopt-cpp replxx cppcodec sdbus-cpp \
+            replxx cppcodec sdbus-cpp \
             ; do
         rm -rf build/{,host-}${PROJECT}-custom/ per-package/{,host-}${PROJECT}/
     done