Update pybind11 in integration test image from 2.9 -> 2.11.

We have had issues in 2.10, and it appears a change upstream is no
longer compatible with version 2.9:

llvm/llvm-project#115307

This updates to 2.11.2, the next minor version, which I have used
locally for a long time. This patch version came out months ago.

Author: mikeurbach

integration_test/Dockerfile

@@ -14,8 +14,8 @@ RUN apt-get update && apt-get install -y \
 RUN apt-get update && apt-get install -y \
   python3.8-dev python3-pip python3.9-dev
 
-RUN python3.8 -m pip install pycapnp psutil pybind11==2.9.1 numpy jinja2 cocotb cocotb_test
-RUN python3.9 -m pip install pycapnp psutil pybind11==2.9.1 numpy jinja2 cocotb cocotb_test
+RUN python3.8 -m pip install pycapnp psutil pybind11==2.11.2 numpy jinja2 cocotb cocotb_test
+RUN python3.9 -m pip install pycapnp psutil pybind11==2.11.2 numpy jinja2 cocotb cocotb_test
 
 RUN apt-get update && apt-get install -y tcl