Problem: ethbloom 0.10 unit test compilation fails on CI

[tomtau]

   Compiling ethbloom v0.10.0
34	error[E0658]: use of unstable library feature 'str_strip': newly added
35	  --> /drone/src/drone/cargo/registry/src/github.com-1ecc6299db9ec823/ethbloom-0.10.0/src/lib.rs:69:1
36	   |
37	69 | / construct_fixed_hash! {
38	70 | |     /// Bloom hash type with 256 bytes (2048 bits) size.
39	71 | |     pub struct Bloom(BLOOM_SIZE);
40	72 | | }
41	   | |_^
42	   |
43	   = note: see issue #67302 <https://github.com/rust-lang/rust/issues/67302> for more information
44	   = help: add `#![feature(str_strip)]` to the crate attributes to enable
45	   = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
46	
47	error: aborting due to previous error
48	
49	For more information about this error, try `rustc --explain E0658`.
50	error: could not compile `ethbloom`.
51	
52	To learn more, run the command again with --verbose.
53	warning: build failed, waiting for other jobs to finish...
54	error: build failed