add figure to crispr assay

assays/CRISPRCas9-basedMutagenesis/README.md

+<img src=dataset\gr1b_lrg.jpg width=100%>
+
+### Figure 1 B) caption
+
+**Figure 1 B).** Schematic overview of CRISPR-Cas9-generated mutant alleles of *GBP1* and *GBP2*.
+
+### Figure 1 B) source
+https://www.cell.com/current-biology/fulltext/S0960-9822(23)01449-5?_returnURL=https%3A%2F%2Flinkinghub.elsevier.com%2Fretrieve%2Fpii%2FS0960982223014495%3Fshowall%3Dtrue#fx1
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