Modify rationale re: SemVer - in some cases it's not so helpful
Modify rationale re: SemVer - in some cases it's not so helpful

There is some controversy about SemVer, esp. when there's only a
single running instance (via continuous delivery).
It is only a SUGGESTED, but it may not be obvious to readers
WHY it is only SUGGESTED, so let's make that clear.
This should help them decide if it's appropriate to their circumstance.

Signed-off-by: David A. Wheeler <9ae72d22d8b894b865a7a496af4fab6320e6abb2@dwheeler.com>

wanganyv/cii-best-practices-badge,linuxfoundation/cii-best-practices-badge,wanganyv/cii-best-practices-badge,linuxfoundation/cii-best-practices-badge,linuxfoundation/cii-best-practices-badge,jdossett/cii-best-practices-badge,linuxfoundation/cii-best-practices-badge,taylorcoursey/cii-best-practices-badge,taylorcoursey/cii-best-practices-badge,wanganyv/cii-best-practices-badge,coreinfrastructure/best-practices-badge,wanganyv/cii-best-practices-badge,jdossett/cii-best-practices-badge,yannickmoy/cii-best-practices-badge,taylorcoursey/cii-best-practices-badge,coreinfrastructure/best-practices-badge,jdossett/cii-best-practices-badge,jdossett/cii-best-practices-badge,coreinfrastructure/best-practices-badge,yannickmoy/cii-best-practices-badge,yannickmoy/cii-best-practices-badge,taylorcoursey/cii-best-practices-badge,yannickmoy/cii-best-practices-badge,coreinfrastructure/best-practices-badge