Merge pull request #245 from NOAA-OWP/fix-link

docs: fix agu presentation link

README.md

@@ -146,4 +146,4 @@ mean_flow = my_dataframe.groupby('usgs_site_code', observed=True).mean()
 ```
 
 ## American Geophysical Union 2021 Fall Meeting Poster
-[OWPHydroTools_AGU2021.pdf](https://github.com/NOAA-OWP/OWP-Presentations/blob/main/AGU_2021/Poster_Presentations/J.Regina_OWPHydroTools_AGU2021.pdf)
+[OWPHydroTools_AGU2021.pdf](https://github.com/NOAA-OWP/OWP-Presentations/blob/main/AGU/AGU%202021/Poster%20Presentations/Regina_AGU_2021.pdf)