libbpf: start v1.7 dev cycle

With libbpf 1.6.0 released, adjust libbpf.map and libbpf_version.h to
start v1.7 development cycles.

Signed-off-by: Andrii Nakryiko <[e-mail]>
Acked-by: Yonghong Song <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Alexei Starovoitov <[e-mail]>

tools/lib/bpf/libbpf.map

···
 		btf__add_decl_attr;
 		btf__add_type_attr;
 } LIBBPF_1.5.0;
+
+LIBBPF_1.7.0 {
+} LIBBPF_1.6.0;

tools/lib/bpf/libbpf_version.h

···
 #define __LIBBPF_VERSION_H
 
 #define LIBBPF_MAJOR_VERSION 1
-#define LIBBPF_MINOR_VERSION 6
+#define LIBBPF_MINOR_VERSION 7
 
 #endif /* __LIBBPF_VERSION_H */