Make bootstrap shell script set ubi to executable #351

Job	Run time
Alpine Linux	1m 38s
FreeBSD-x86_64 with rust stable	53s
Linux-x86_64 with rust stable	22s
Linux-x86_64 (rustls-native-roots) with rust stable	1m 27s
Linux-x86_64 (native-tls) with rust stable	1m 50s
Linux-x86_64 (native-tls-vendored) with rust stable	1m 48s
Linux-aarch64 with rust stable	1m 48s
Linux-arm with rust stable	1m 49s
Linux-i686 with rust stable	1m 48s
Linux-powerpc with rust stable	1m 50s
Linux-powerpc64 with rust stable	1m 49s
Linux-powerpc64le with rust stable	1m 44s
Linux-riscv64 with rust stable	1m 49s
Linux-s390x with rust stable	1m 48s
NetBSD-x86_64 with rust stable	1s
Windows-aarch64 with rust stable	1m 32s
Windows-i686 with rust stable	1m 8s
Windows-x86_64 with rust stable	1m 13s
macOS-x86_64 with rust stable	1m 37s
macOS-aarch64 with rust stable	1m 2s
Linux-x86_64 with rust beta	51s
Linux-x86_64 with rust nightly	50s
	30m 37s

Provide feedback