Add .git_archival.txt

This will ensure that setuptools-scm also works with `git archive` outputs, and not only with repo clones.

Author: dweindl

.gitattributes

@@ -0,0 +1 @@
+src/python/.git_archival.txt  export-subst

src/python/.git_archival.txt

@@ -0,0 +1,3 @@
+node: $Format:%H$
+node-date: $Format:%cI$
+describe-name: $Format:%(describe:tags=true,match=*[0-9]*)$

src/python/build.sh

@@ -25,7 +25,7 @@ mkdir $BUILD_DIR
 # Copy code
 cp -r \
   $CODE_DIR \
-  "pyproject.toml" "MANIFEST.in" \
+  "pyproject.toml" "MANIFEST.in" ".git_archival.txt" \
   "../../LICENSE" "../../README.md" \
   $BUILD_DIR
 # Remove link