refactor: migrate from yosys to yowasp-yosys

yowasp-yosys can be installed from pip, so we no longer require the user to install yosys separately.

also freeze requirements.txt versions for reproducible builds

requirements.txt

@@ -1,7 +1,29 @@
-pytz
-gdstk
-stripe
-GitPython
-cairosvg
-requests
-PyYAML
+appdirs==1.4.4
+cairocffi==1.6.0
+CairoSVG==2.7.0
+certifi==2023.5.7
+cffi==1.15.1
+charset-normalizer==3.1.0
+click==8.1.3
+cssselect2==0.7.0
+defusedxml==0.7.1
+gdstk==0.9.42
+gitdb==4.0.10
+GitPython==3.1.31
+idna==3.4
+importlib-resources==5.12.0
+numpy==1.24.3
+Pillow==9.5.0
+pycparser==2.21
+pytz==2023.3
+PyYAML==6.0
+requests==2.31.0
+smmap==5.0.0
+stripe==5.4.0
+tinycss2==1.2.1
+urllib3==2.0.3
+wasmtime==9.0.0
+webencodings==0.5.1
+yowasp-runtime==1.22
+yowasp-yosys==0.30.0.0.post538
+zipp==3.15.0