fixed broken links in 4.7.0 release notes

Author: raffazizzi

P5/ReleaseNotes/readme-4.7.0.xml

@@ -32,7 +32,7 @@ See the file COPYING.txt for details
         community. As always, the majority of these changes and corrections are a consequence of
         feature requests or bugs reported by the TEI community using the GitHub tracking system. A
         full list of the issues resolved in the course of this release cycle may be found under the
-          <ref target="https://github.com/TEIC/TEI/milestone/15?closed=1">4.7.0 milestone</ref>.</p>
+          <ref target="https://github.com/TEIC/TEI/milestone/17?closed=1">4.7.0 milestone</ref>.</p>
       <p>The following changes are particularly worth highlighting in this release:
 
       <list>
@@ -49,7 +49,7 @@ See the file COPYING.txt for details
             elements, but still allows older ways of labeling events. See <ref
               target="https://github.com/TEIC/TEI/pull/2483">PR #2483</ref>. </item>
           <item>The <gi>taxonomy</gi> and <gi>category</gi> elements are now added to <name
-              type="class">att.datacat</name> (<ref target="https://github.com/TEIC/TEI/issues/2419"
+              type="class">att.datcat</name> (<ref target="https://github.com/TEIC/TEI/issues/2419"
               >#2419</ref>).</item>
         </list>
 
@@ -149,7 +149,7 @@ See the file COPYING.txt for details
         conversions). The Stylesheets are maintained separately from the Guidelines at <ref
           target="https://github.com/TEIC/Stylesheets">https://github.com/TEIC/Stylesheets</ref>. A
         full list of the issues resolved in the course of this release cycle may be found under the
-          <ref target="https://github.com/TEIC/Stylesheets/milestone/14?closed=1">7.56.0
+          <ref target="https://github.com/TEIC/Stylesheets/milestone/16?closed=1">7.56.0
           milestone</ref>.</p>
 
       <p>Highlights of this release include:<list>