travis: Make sure to install all python dependencies

.travis.yml

@@ -5,7 +5,7 @@ notifications:
   email: false
 
 before_install:
-  sudo apt-get install -y libsqlite3-dev cppcheck valgrind gcc-4.8 gettext libc6-dev-armhf-cross libc6-dev-arm64-cross gcc-aarch64-linux-gnu gcc-arm-linux-gnueabihf qemu-user-static binfmt-support
+  sudo apt-get install -y libsqlite3-dev cppcheck valgrind gcc-4.8 gettext libc6-dev-armhf-cross libc6-dev-arm64-cross gcc-aarch64-linux-gnu gcc-arm-linux-gnueabihf qemu-user-static binfmt-support libsecp256k1-dev
 
 env:
   - ARCH=64 SOURCE_CHECK_ONLY=true COPTFLAGS="-O3"

.travis/build.sh

@@ -28,10 +28,20 @@ if [ ! -f dependencies/bin/bitcoind ]; then
 fi
 
 pyenv global 3.7
-pip3 install --user --quiet -r requirements.txt -r tests/requirements.txt -r doc/requirements.txt
-pip3 install --quiet \
+
+# Update pip first, may save us the compilation of binary packages in the next call
+pip3 install --user -U --quiet --progress-bar off \
+     pip \
      pytest-test-groups==1.0.3
 
+pip3 install --user -U --quiet --progress-bar off \
+     -r requirements.txt \
+     -r tests/requirements.txt \
+     -r doc/requirements.txt \
+     -r contrib/pyln-client/requirements.txt \
+     -r contrib/pyln-proto/requirements.txt \
+     -r contrib/pyln-testing/requirements.txt
+
 echo "Configuration which is going to be built:"
 echo -en 'travis_fold:start:script.1\\r'
 ./configure CC="$CC"