Bump python/{3.4 => 3.8}

Python 3.8 is currently the minimum required version we support, see
kaitai-io/kaitai_struct_python_runtime@3e0f9a9

Author: generalmimon

.github/workflows/build.yml

@@ -77,7 +77,7 @@ jobs:
           - target: php
             implementation: '8.4'
           - target: python
-            implementation: '3.4'
+            implementation: '3.8'
           - target: python
             implementation: '3.14'
           - target: ruby

src/python/3.4-linux-x86_64/Dockerfile src/python/3.8-linux-x86_64/Dockerfilesrc/python/3.4-linux-x86_64/Dockerfile renamed to src/python/3.8-linux-x86_64/Dockerfile

@@ -1,4 +1,4 @@
-FROM python:3.4-alpine
+FROM python:3.8-alpine
 
 # Copy files common for all images
 COPY 4img/* ./
@@ -10,6 +10,6 @@ RUN ./prepare-alpine-init && ./prepare-alpine-ruby && ./prepare-alpine-uninit
 # Validate that we've got correct version, e.g. something like this:
 #
 # $ python --version
-# Python 3.4.10
+# Python 3.8.20
 
-RUN ./validate '^Python 3\.4\.'
+RUN ./validate '^Python 3\.8\.'