Main add graph unit (#632)

* Add the Unit field to Graph Panels

* Update changelog for Graph Panel

Author: padraic-padraic

CHANGELOG.rst

@@ -10,6 +10,7 @@ Changelog
 .. _`docs`: https://grafana.com/docs/grafana/latest/dashboards/build-dashboards/manage-dashboard-links/#dashboard-links
 
 * Added ...
+* Add Unit option for Graph panel
 * Added Minimum option for Timeseries
 * Added Maximum option for Timeseries
 * Added Number of decimals displays option for Timeseries

grafanalib/core.py

@@ -2104,7 +2104,7 @@ class Graph(Panel):
     :param stack: Each series is stacked on top of another
     :param percentage: Available when Stack is selected. Each series is drawn as a percentage of the total of all series
     :param thresholds: List of GraphThresholds - Only valid when alert not defined
-
+    :param unit: Set Y Axis Unit
     """
 
     alert = attr.ib(default=None)
@@ -2138,6 +2138,7 @@ class Graph(Panel):
         validator=instance_of(Tooltip),
     )
     thresholds = attr.ib(default=attr.Factory(list))
+    unit = attr.ib(default='', validator=instance_of(str))
     xAxis = attr.ib(default=attr.Factory(XAxis), validator=instance_of(XAxis))
     try:
         yAxes = attr.ib(
@@ -2157,6 +2158,11 @@ def to_json_data(self):
             'aliasColors': self.aliasColors,
             'bars': self.bars,
             'error': self.error,
+            'fieldConfig': {
+                'defaults': {
+                    'unit': self.unit
+                },
+            },
             'fill': self.fill,
             'grid': self.grid,
             'isNew': self.isNew,