Bump third-party/libswiftnav from 4d1dace to 88fa9f1 (#55)

dependabot[bot] · web-flow · commit df1c2720202b · 2021-06-28T22:54:23.000Z
diff --git a/third-party/libswiftnav b/third-party/libswiftnav
@@ -1 +1 @@
-Subproject commit 4d1dace3469708a48a904c5192dc00cea5544f22
+Subproject commit 88fa9f1d2f4ef23e1784c465d0d89e41162b36bb
