Update containerization-docker-best-practices.instructions.md (#137)

Reduce redundancy; improve coverage of excluding .env.* files.

Author: inquinity

instructions/containerization-docker-best-practices.instructions.md

@@ -174,8 +174,7 @@ RUN apt-get update && \
 - **Example (Comprehensive .dockerignore):**
 ```dockerignore
 # Version control
-.git
-.gitignore
+.git*
 
 # Dependencies (if installed in container)
 node_modules
@@ -189,8 +188,7 @@ build
 *.so
 
 # Development files
-.env
-.env.local
+.env.*
 *.log
 coverage
 .nyc_output
@@ -206,9 +204,8 @@ coverage
 Thumbs.db
 
 # Documentation
-README.md
-docs/
 *.md
+docs/
 
 # Test files
 test/