Makefile: add experimental report-tool grype

`grype` is a security scanner for container images etc. Golang
tools are among the supported scan targets.

    $> grype .
    ✔ Vulnerability DB        [no update available]
    ✔ Indexed .
    ✔ Cataloged packages      [66 packages]
    ✔ Scanning image...       [2 vulnerabilities]
    ├── 0 critical, 2 high, 0 medium, 0 low, 0 negligible
    └── 0 fixed
    NAME                            INSTALLED  FIXED-IN  TYPE       VULNERABILITY        SEVERITY
    github.com/opencontainers/runc  v1.1.4               go-module  GHSA-vpvm-3wq2-2wvm  High

This commit adds it to the Makefile to have it at hand every now and
then.

Makefile

@@ -89,6 +89,10 @@ report-gosec:
 	@echo '####################################################################'
 	gosec ./...
 
+report-grype:
+	@echo '####################################################################'
+	grype .
+
 fetch-report-tools:
 	go install github.com/fzipp/gocyclo/cmd/gocyclo@latest
 	go install github.com/client9/misspell/cmd/misspell@latest
@@ -97,4 +101,7 @@ fetch-report-tools:
 	go install golang.org/x/vuln/cmd/govulncheck@latest
 	go install github.com/securego/gosec/v2/cmd/gosec@latest
 
+fetch-report-tool-grype:
+	go install github.com/anchore/grype@latest
+
 .PHONY: cciu bin/cciu