ci: use upstream yosys and add ccache in GH actions

Signed-off-by: Alessandro Comodi <acomodi@antmicro.com>

.github/workflows/ci.yml

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index e9422ad..9a5b094 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -28,8 +28,13 @@
           pkg-config libboost-system-dev libboost-python-dev \
           libboost-filesystem-dev zlib1g-dev clang-format-8 cmake
 
+    - name: ccache
+      uses: hendrikmuhs/ccache-action@v1
+
     - name: Install Yosys
-      run: source .github/workflows/setup.sh
+      run: |
+        export PATH="/usr/lib/ccache:/usr/local/opt/ccache/libexec:$PATH"
+        source .github/workflows/setup.sh
       env:
         OS: ${{ runner.os }}
 

.github/workflows/setup.sh

diff --git a/.github/workflows/setup.sh b/.github/workflows/setup.sh
index 9e5b3f7..41175ac 100644
--- a/.github/workflows/setup.sh
+++ b/.github/workflows/setup.sh
@@ -46,7 +46,7 @@
         mkdir -p ~/.local-src
         mkdir -p ~/.local-bin
         cd ~/.local-src
-        git clone https://github.com/SymbiFlow/yosys.git -b master+wip
+        git clone https://github.com/YosysHQ/yosys.git
         cd yosys
         make config-gcc # Build Yosys using GCC
         PREFIX=$HOME/.local-bin make -j$(nproc)