NOISSUE - Migrate gocoap library from v2 to v3.3

.gitignore

@@ -1,3 +1,6 @@
+# Copyright (c) Abstract Machines
+# SPDX-License-Identifier: Apache-2.0
+
 # Binaries for programs and plugins
 *.exe
 *.exe~

Makefile

@@ -1,3 +1,6 @@
+# Copyright (c) Abstract Machines
+# SPDX-License-Identifier: Apache-2.0
+
 all:
 	CGO_ENABLED=0 GOOS=linux go build -ldflags "-s -w" -o build/coap-cli-linux cmd/main.go
 	CGO_ENABLED=0 GOOS=darwin go build -ldflags "-s -w" -o build/coap-cli-darwin cmd/main.go

README.md

@@ -1,29 +1,57 @@
 # CoAP CLI
-Simple CoAP cli client written in Go.
 
+Simple CoAP cli client written in Go.
 
 ## Usage
-Pre-built binary can be found here: https://github.com/mainflux/coap-cli/releases/tag/v0.3.3.
-When running, please provide following format:
-`coap-cli` followed by method code (`get`, `put`, `post`, `delete`) and CoAP URL. After that, you can pass following flags:
 
-| Flag | Description                                    | Default value    |
-| ---- | ---------------------------------------------- | ---------------- |
-| o    | observe   option - only valid with GET request | false            |
-| auth | auth option sent as URI Query                  | ""               |
-| h    | host                                           | "localhost"      |
-| p    | port                                           | "5683"           |
-| d    | data to be sent in POST or PUT                 | ""               |
-| cf   | content format                                 | 50 (JSON format) |
+```bash
+Usage:
+  coap-cli [command]
+
+Available Commands:
+  completion  Generate the autocompletion script for the specified shell
+  delete      Perform a DELETE request on a COAP resource
+  get         Perform a GET request on a COAP resource
+  help        Help about any command
+  post        Perform a POST request on a COAP resource
+  put         Perform a PUT request on a COAP resource
+
+Flags:
+  -a, --auth string           Auth
+  -c, --content-format int    Content format (default 50)
+  -h, --help                  help for coap-cli
+  -H, --host string           Host (default "localhost")
+  -k, --keep-alive uint       Send a ping after interval seconds of inactivity. If not specified (or 0), keep-alive is disabled (default).
+  -m, --max-retries uint32    Max retries for keep alive (default 10)
+  -O, --options num,text      Add option num with contents of text to the request. If the text begins with 0x, then the hex text (two [0-9a-f] per byte) is converted to binary data.
+  -p, --port string           Port (default "5683")
+  -v, --verbose               Verbose output
+  -d, --data string           Data(default "") - only available for put, post and delete commands
+  -o, --observe bool          Observe - only available for get command
+
+Use "coap-cli [command] --help" for more information about a command
+```
+
+The options flag accepts a comma separated string comprising of the optionID defined by [RFC-7252](https://datatracker.ietf.org/doc/html/rfc7252) and a string or hex value. Hex values are used to set options that require numerical values e.g observe, maxAge
 
-## Examples:
+## Examples
 
 ```bash
-coap-cli get channels/0bb5ba61-a66e-4972-bab6-26f19962678f/messages/subtopic -auth 1e1017e6-dee7-45b4-8a13-00e6afeb66eb -o
+coap-cli get channels/0bb5ba61-a66e-4972-bab6-26f19962678f/messages/subtopic --auth 1e1017e6-dee7-45b4-8a13-00e6afeb66eb -o
 ```
+
+```bash
+coap-cli get channels/0bb5ba61-a66e-4972-bab6-26f19962678f/messages/subtopic --options 6,0x00 --options 15,auth=1e1017e6-dee7-45b4-8a13-00e6afeb66eb
+```
+
 ```bash
-coap-cli post channels/0bb5ba61-a66e-4972-bab6-26f19962678f/messages/subtopic -auth 1e1017e6-dee7-45b4-8a13-00e6afeb66eb -d "hello world"
+coap-cli post channels/0bb5ba61-a66e-4972-bab6-26f19962678f/messages/subtopic --auth 1e1017e6-dee7-45b4-8a13-00e6afeb66eb -d "hello world"
 ```
+
+```bash
+coap-cli post channels/0bb5ba61-a66e-4972-bab6-26f19962678f/messages/subtopic --auth 1e1017e6-dee7-45b4-8a13-00e6afeb66eb -d "hello world" -H 0.0.0.0 -p 1234
+```
+
 ```bash
-coap-cli post channels/0bb5ba61-a66e-4972-bab6-26f19962678f/messages/subtopic -auth 1e1017e6-dee7-45b4-8a13-00e6afeb66eb -d "hello world" -h 0.0.0.0 -p 1234
+coap-cli post channels/0bb5ba61-a66e-4972-bab6-26f19962678f/messages/subtopic -options 15,auth=1e1017e6-dee7-45b4-8a13-00e6afeb66eb -d "hello world" -H 0.0.0.0 -p 5683
 ```