Go 1.15rc1 error format change in ParseDuration

[eclipseo]

Describe the bug

Testing    in: /builddir/build/BUILD/go-toml-1.8.0/_build/src
         PATH: /builddir/build/BUILD/go-toml-1.8.0/_build/bin:/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/sbin
       GOPATH: /builddir/build/BUILD/go-toml-1.8.0/_build:/usr/share/gocode
  GO111MODULE: off
      command: go test -buildmode pie -compiler gc -ldflags "-X github.com/pelletier/go-toml/version=1.8.0 -extldflags '-Wl,-z,relro -Wl,--as-needed  -Wl,-z,now -specs=/usr/lib/rpm/redhat/redhat-hardened-ld '"
      testing: github.com/pelletier/go-toml
github.com/pelletier/go-toml
{Hello 3.5 {One} [{Two} {Three}]}
--- FAIL: TestUnmarshalBadDuration (0.00s)
    marshal_test.go:2157: unexpected error: (1, 1): Can't convert 1z(string) to time.Duration. time: unknown unit "z" in duration "1z"
FAIL

To Reproduce
Running go test.

Expected behavior
Tests pass.

Versions

• go-toml: version 1.8.0
• go: version Go 1.15 rc 1
• operating system: Fedora Linux Rawhide

Additional context
The error message was modified to add quote around 1z and z, so it is not recognized by

go-toml/marshal_test.go

Line 2199 in 34de94e

if err.Error() != "(1, 1): Can't convert 1z(string) to time.Duration. time: unknown unit z in duration 1z" {

[moorereason]

Due to golang/go@201cb04.

[pelletier]

Good catch! Thank you for reporting.

[pelletier]

This should be fixed in the latest commit. Feel free to reopen if it doesn't work for you. Sorry it took so long :(