Fix python 3.8 test by running build with 3.8 image (#322)

* Attempt to fix python 3.8 dependency issue by rewriting upstream Dockerfile

* Typo

* Have to use ENV after FROM in dockerfile

* Another attempt to support python 3.8

* Better regex

* Improve comment on why this docker bit is necessary

python/build-layer.sh

@@ -25,6 +25,14 @@ echo "Modified python wrapper requirements:"
 cat requirements.txt
 cd ../..
 
+# FIXME no good way to specify python version requirement to pip; use 3.8 runtime/setuptools image
+# This block can be removed once python 3.8 reaches "no updates" aws deprecation status in March 2025
+sed -i 's/runtime=python3.*/runtime=python3.8/' otel/Dockerfile
+echo "Modified Dockerfile:"
+cat otel/Dockerfile
+echo "----"
+
+
 echo "Building OTel Lambda python"
 rm -rf build
 ./build.sh