add note to doxygen comments

Author: alexbruy

src/analysis/network/qgsdistancestrategy.h

@@ -20,6 +20,7 @@
 
 /** \ingroup analysis
  * \class QgsDistanceStrategy
+ * \note added in QGIS 3.0
  * \brief Strategy for caclucating edge cost based on its length. Should be
  * used for finding shortest path between two points.
  */

src/analysis/network/qgsgraph.h

@@ -36,6 +36,7 @@ class QgsGraphVertex;
 /**
  * \ingroup analysis
  * \class QgsGraphEdge
+ * \note added in QGIS 3.0
  * \brief This class implements a graph edge
  */
 class ANALYSIS_EXPORT QgsGraphEdge

src/analysis/network/qgsstrategy.h

@@ -24,6 +24,7 @@
 /**
  * \ingroup analysis
  * \class QgsStrategy
+ * \note added in QGIS 3.0
  * \brief QgsStrategy defines strategy used for calculation of the edge cost. For example it can
  * take into account travel distance, amount of time or money. Currently there are two strategies
  * implemented in the analysis library: QgsDistanceStrategy and QgsSpeedStrategy.