Fix documentation links

Author: maxnoe

README.rst

@@ -22,7 +22,7 @@ it can be used to process also data from other Imaging Atmospheric
 Cherenkov Telescopes (IACTs).
 
 - **Source code:** https://github.com/cta-observatory/pyirf
-- **Documentation:** https://cta-observatory.github.io/pyirf/
+- **Documentation:** https://pyirf.readthedocs.io/
 
 Citing this software
 --------------------

docs/contribute.rst

@@ -135,7 +135,7 @@ Further details
 
 Please also have a look at the
 
-- ``ctapipe`` `development guidelines <https://cta-observatory.github.io/ctapipe/development/index.html>`__
+- ``ctapipe`` `development guidelines <https://ctapipe.readthedocs.io/en/latest/developer-guide/>`__
 - The `Open Gamma-Ray Astronomy data formats <https://gamma-astro-data-formats.readthedocs.io/en/latest/>`__
   which also describe the IRF formats and their definitions.
 - ``ctools`` `documentation page on IRFs <http://cta.irap.omp.eu/ctools/users/user_manual/irf_cta.html>`__

docs/notebooks/fact_example.ipynb

@@ -119,7 +119,7 @@
     "`pyirf` does not prescribe or use a specific DL2 *file* format.\n",
     "You need to read the data into an `astropy.table.QTable` following our conventions, detailed in the docs here: \n",
     "\n",
-    "<https://cta-observatory.github.io/pyirf/introduction.html#dl2-event-lists>\n",
+    "<https://pyirf.readthedocs.io/en/latest/introduction.html#dl2-event-lists>\n",
     "\n",
     "The FACT-Tools / aict-tools analysis chain uses a column-oriented hdf5 file written using h5py.  \n",
     "Unfortunately, units have to be known and are not in the metadata."