use absolute path for swift test libldk.a

Author: arik-so

.github/workflows/swift.yml

@@ -72,7 +72,7 @@ jobs:
             -   name: Test Swift bindings package
                 run: |
                     cd ci/LDKSwift
-                    LDK_C_BINDINGS_BASE="../../ldk-c-bindings" RUST_BACKTRACE=1 ../../swift-5.4.2-RELEASE-ubuntu20.04/usr/bin/swift test -v
+                    LDK_C_BINDINGS_BASE="/home/runner/work/ldk-swift/ldk-swift/ldk-c-bindings" RUST_BACKTRACE=1 ../../swift-5.4.2-RELEASE-ubuntu20.04/usr/bin/swift test -v
             -   name: Check that the latest headers are in the swift repo
                 run: |
                     git diff --exit-code