fix: remove cocotb from requirements

It's only needed by the wokwi testing library, and it causes version conflicts with the user/tt-multiplexer provided cocotb versions.

pyproject.toml

@@ -5,7 +5,6 @@ dynamic = ["version"]
 dependencies = [
     "CairoSVG",
     "chevron",
-    "cocotb",
     "gdstk",
     "GitPython",
     "klayout<0.30.0,>=0.29.0",

requirements.txt

@@ -20,8 +20,6 @@ chevron==0.14.0
     # via tt-support-tools (pyproject.toml)
 click==8.2.1
     # via yowasp-yosys
-cocotb==2.0.0
-    # via tt-support-tools (pyproject.toml)
 contourpy==1.3.3
     # via matplotlib
 cssselect2==0.8.0
@@ -34,8 +32,6 @@ distlib==0.4.0
     # via virtualenv
 filelock==3.18.0
     # via virtualenv
-find-libpython==0.4.1
-    # via cocotb
 fonttools==4.60.1
     # via matplotlib
 gdstk==0.9.60

testing/requirements.txt

@@ -0,0 +1 @@
+cocotb==1.9.2