Handle unparseable data in Docker event stream

Not clear what this actually is, but hopefully this will let us skip it,
and logging it should help diagnose the issue, if it's actually
something important (but I suspect it's actually some whitespace-only
keep-alive data or similar).

src/interceptors/docker/docker-networking.ts

@@ -35,7 +35,14 @@ function getDockerEventStream(docker: Docker) {
             EventStream.split(),
             EventStream.mapSync((buffer: Buffer) => buffer.toString('utf8')),
             EventStream.filterSync((line: string) => line.length > 0),
-            EventStream.mapSync((rawLine: string) => JSON.parse(rawLine))
+            EventStream.mapSync((rawLine: string) => {
+                try {
+                    return JSON.parse(rawLine);
+                } catch (e) {
+                    console.warn(`Unparseable Docker event data: ${rawLine}`);
+                    return {};
+                }
+            })
         );
 
         // We expose the stream immediately, even though no data is coming yet