Drop support for node.js engines below v10

It's a common practice to drop support for non-LTS Node versions,
as it allows to reduce the maintenance burden. See more at:
https://nodejs.org/en/about/releases/

Makefile

@@ -3,7 +3,7 @@ JSON=amqp-rabbitmq-0.9.1.json
 RABBITMQ_CODEGEN=https://raw.githubusercontent.com/rabbitmq/rabbitmq-codegen
 AMQP_JSON=$(RABBITMQ_CODEGEN)/$(RABBITMQ_SRC_VERSION)/$(JSON)
 
-NODEJS_VERSIONS='0.8' '0.9' '0.10' '0.11' '0.12' '1.8.4' '2.5' '3.3' '4.9' '5.12' '6.17' '8.17' '9.11' '10.21' '11.15' '12.18' '13.14' '14.5' '15.8'
+NODEJS_VERSIONS='10.21' '11.15' '12.18' '13.14' '14.5' '15.8'
 
 MOCHA=./node_modules/.bin/mocha
 _MOCHA=./node_modules/.bin/_mocha

package.json

@@ -9,7 +9,7 @@
     "url": "https://github.com/squaremo/amqp.node.git"
   },
   "engines": {
-    "node": ">=0.8 <=15"
+    "node": ">=10 <=15"
   },
   "dependencies": {
     "bitsyntax": "~0.1.0",