fix: use an absolute path in docker entrypoint (#4263)

With a relative path, containers started with a different working
directory will fail to find the entrypoint

Fixes: #4252
Signed-off-by: James Callahan <jamescallahan@bitgo.com>

Co-authored-by: shuting <shuting@nirmata.com>

cmd/cli/kubectl-kyverno/Dockerfile

@@ -31,4 +31,4 @@ LABEL maintainer="Kyverno"
 
 COPY --from=builder /output/kyverno /
 
-ENTRYPOINT ["./kyverno"]
+ENTRYPOINT ["/kyverno"]

cmd/initContainer/Dockerfile

@@ -32,4 +32,4 @@ LABEL maintainer="Kyverno"
 COPY --from=builder /output/kyvernopre /
 
 
-ENTRYPOINT ["./kyvernopre"]
+ENTRYPOINT ["/kyvernopre"]

cmd/kyverno/Dockerfile

@@ -34,4 +34,4 @@ FROM ghcr.io/distroless/static:latest
 LABEL maintainer="Kyverno"
 COPY --from=builder /output/kyverno /
 
-ENTRYPOINT ["./kyverno"]
+ENTRYPOINT ["/kyverno"]