fix: specify portable sed arguments (#1332)

Copied from https://github.com/open-telemetry/opentelemetry-cpp/blob/ca08c5a34ad4af1b6b392c8bf5fc26a5210a2f2c/tools/format.sh#L16-L19.

Author: kriswuollett

opentelemetry-semantic-conventions/scripts/generate-consts-from-spec.sh

@@ -42,10 +42,15 @@ docker run --rm \
 	--output /output/resource.rs \
 	--parameters conventions=resource
 
+SED=(sed -i)
+if [[ "$(uname)" = "Darwin" ]]; then
+  SED=(sed -i "")
+fi
+
 # Keep `SCHEMA_URL` key in sync with spec version
-sed -i "s/\(opentelemetry.io\/schemas\/\)[^\"]*\"/\1$SPEC_VERSION\"/" src/lib.rs
+"${SED[@]}" "s/\(opentelemetry.io\/schemas\/\)[^\"]*\"/\1$SPEC_VERSION\"/" src/lib.rs
 
 # handle doc generation failures
-sed -i 's/\[2\]\.$//' src/resource.rs # remove trailing [2] from few of the doc comments
+"${SED[@]}" 's/\[2\]\.$//' src/resource.rs # remove trailing [2] from few of the doc comments
 
 cargo fmt