Updating changelog for 1.8.0 release

CHANGES.rst

@@ -1,9 +1,14 @@
-1.8.0 (unreleased)
+1.8.0 (2022-08-22)
 ------------------
 
 New Features
 ^^^^^^^^^^^^
 
+- Implemented uncertainty propagation for analysis functions. [#938, #939, #961, #968]
+
+- Model fitting with ``fit_lines`` now returns uncertainties from the underlying scipy
+  fitter by default. [#962]
+
 Bug Fixes
 ^^^^^^^^^
 
@@ -19,6 +24,9 @@ Other Changes and Additions
   in favor of the more explicit set_redshift_to, shift_spectrum_to, and
   set_radial_velocity_to methods. [#946, #943]
 
+- ``estimate_line_parameters`` now calculates estimates based on the selected
+  region, rather than the entire spectrum. [#962]
+
 1.7.0 (2022-02-21)
 ------------------