Address deprecation warning (#24)

* address deprecation warning

* satisfy hassfest validation

custom_components/leafspy/device_tracker.py

@@ -7,7 +7,7 @@
     ATTR_LONGITUDE,
     ATTR_BATTERY_LEVEL,
 )
-from homeassistant.components.device_tracker.const import SOURCE_TYPE_GPS
+from homeassistant.components.device_tracker.const import SourceType
 from homeassistant.components.device_tracker.config_entry import (
     TrackerEntity
 )
@@ -118,7 +118,7 @@ def should_poll(self):
     @property
     def source_type(self):
         """Return the source type of the car."""
-        return SOURCE_TYPE_GPS
+        return SourceType.GPS
 
     @property
     def device_info(self):

custom_components/leafspy/manifest.json

@@ -1,12 +1,12 @@
 {
   "domain": "leafspy",
   "name": "Leaf Spy",
+  "codeowners": ["@jesserockz"],
+  "config_flow": true,
+  "dependencies": ["http"],
   "documentation": "https://github.com/jesserockz/ha-leafspy/blob/master/README.md",
+  "iot_class": "local_push",
   "issue_tracker": "https://github.com/jesserockz/ha-leafspy/issues",
   "requirements": [],
-  "dependencies": ["http"],
-  "codeowners": ["@jesserockz"],
-  "config_flow": true,
-  "version": "0.2.0",
-  "iot_class": "local_push"
+  "version": "0.2.0"
 }

custom_components/leafspy/strings.json

@@ -1,10 +1,10 @@
 {
   "config": {
     "abort": {
-      "one_instance_allowed": "Only a single instance is necessary."
+      "one_instance_allowed": "You may have only one instance of Leaf Spy installed, and you appear to have installed one already."
     },
     "create_entry": {
-      "default": "\n\nOpen the Leaf Spy app, go to `'Menu'` -> `'Settings'` and scroll down to `'Server'`. \nChange the following settings:\n - `'Enable'`: Yes\n - `'Send Interval'` can be whatever you prefer.\n - `'ID'`: `'<Car Name>'`\n - `'PW'`: {secret}\n - `'Http'` or `'Https'` depending on the access to your Home Assistant install.\n - `'URL'`: {url} - Note: **Do not** add http or https to the URL."
+      "default": "\n\nOpen the Leaf Spy app, go to `'Menu'` -> `'Settings'` and scroll down to `'Server'`. \nChange the following settings:\n - `'Enable'`: Yes\n - `'Send Interval'` can be whatever you prefer.\n - `'ID'`: `'(Car Name)'`\n - `'PW'`: {secret}\n - `'Http'` or `'Https'` depending on the access to your Home Assistant install.\n - `'URL'`: {url} - Note: **Do not** add http or https to the URL."
     },
     "step": {
       "user": {

custom_components/leafspy/translations/en.json

@@ -1,10 +1,10 @@
 {
   "config": {
     "abort": {
-      "one_instance_allowed": "Only a single instance is necessary."
+      "one_instance_allowed": "You may have only one instance of Leaf Spy installed, and you appear to have installed one already."
     },
     "create_entry": {
-      "default": "\n\nOpen the Leaf Spy app, go to `'Menu'` -> `'Settings'` and scroll down to `'Server'`. \nChange the following settings:\n - `'Enable'`: Yes\n - `'Send Interval'` can be whatever you prefer.\n - `'ID'`: `'<Car Name>'`\n - `'PW'`: {secret}\n - `'Http'` or `'Https'` depending on the access to your Home Assistant install.\n - `'URL'`: {url} - Note: **Do not** add http or https to the URL."
+      "default": "\n\nOpen the Leaf Spy app, go to `'Menu'` -> `'Settings'` and scroll down to `'Server'`. \nChange the following settings:\n - `'Enable'`: Yes\n - `'Send Interval'` can be whatever you prefer.\n - `'ID'`: `'(Car Name)'`\n - `'PW'`: {secret}\n - `'Http'` or `'Https'` depending on the access to your Home Assistant install.\n - `'URL'`: {url} - Note: **Do not** add http or https to the URL."
     },
     "step": {
       "user": {