Invalid RELEASE_NOTES.md leads to "The input sequence was empty."

[matthid]

Description

Script reported an error:
-> ArgumentException: The input sequence was empty.
   Parameter name: source
   StackTrace:
        at Microsoft.FSharp.Collections.SeqModule.Head[T](IEnumerable`1 source)
        at <StartupCode$build_70E2D21C78BA0A6B7FD93E04CE30EDBCEA733E78BFE81CA6D770207BD042644F>.$Build$fsx.main@() in E:\Projects\vsts-fsharp\build.fsx:line 27

Repro steps

RELEASE_NOTES.md:

# 1.3.7

* Bugfixes and public release

# 1.3.2

* Fix various bugs in the FAKE runner.

Expected behavior

Improved error message

Actual behavior

"The input sequence was empty"

Known workarounds

Fix RELEASE_NOTES.md