Merge pull request #397 from digitalearthafrica/geomad_desc

fix description in ls89 geomad

Author: cbur24

services/ows_refactored/surface_reflectance/ows_gm_ls8_ls9_annual_cfg.py

@@ -18,7 +18,7 @@
 
 More techincal information about the GeoMAD product can be found in the User Guide (https://docs.digitalearthafrica.org/en/latest/data_specs/GeoMAD_specs.html)
 
-This product has a spatial resolution of 30 m and is available annually from 2013.
+This product has a spatial resolution of 30 m and is available annually starting from 2021.
 
 It is derived from USGS Collection 2, Level 2 Landsat 8 & 9 surface reflectance data.