remove unsupported postgres versions

Author: asherf

README.md

@@ -6,7 +6,7 @@
 
 Prometheus exporter for PostgreSQL server metrics.
 
-CI Tested PostgreSQL versions: `9.1`, `9.2`, `9.3`, `9.4`, `9.5`, `9.6`, `10`, `11`
+CI Tested PostgreSQL versions: `9.4`, `9.5`, `9.6`, `10`, `11`
 
 ## Quick Start
 This package is available for Docker:

cmd/postgres_exporter/tests/test-smoke

@@ -26,9 +26,6 @@ echo "Test Binary: $test_binary" 1>&2
 cd "$DIR" || exit 1
 
 VERSIONS=( \
-    9.1 \
-    9.2 \
-    9.3 \
     9.4 \
     9.5 \
     9.6 \