Bump third-party/libswiftnav from 68994ab to 74c534e

dependabot[bot] · web-flow · commit 2547fa2a241c · 2020-10-23T13:09:26.000Z
Bumps [third-party/libswiftnav](https://github.com/swift-nav/libswiftnav) from `68994ab` to `74c534e`. - [Release notes](https://github.com/swift-nav/libswiftnav/releases) - [Commits](swift-nav/libswiftnav@68994ab...74c534e) Signed-off-by: dependabot[bot] <support@github.com>
diff --git a/third-party/libswiftnav b/third-party/libswiftnav
@@ -1 +1 @@
-Subproject commit 68994ab134c93e726fd8322996d9e7089ae2e8c9
+Subproject commit 74c534e266a7de21b6a3826142b77099c23c8fd7
