downgrade bundler 2.7

Gemfile.legacy.lock

@@ -84,7 +84,7 @@ GEM
       descendants_tracker (~> 0.0.4)
       ice_nine (~> 0.11.0)
       thread_safe (~> 0.3, >= 0.3.1)
-    base64 (0.1.1)
+    base64 (0.2.0)
     batch-loader (1.5.0)
     bcrypt (3.1.19)
     better_html (1.0.16)
@@ -150,7 +150,7 @@ GEM
     crass (1.0.6)
     css_parser (1.16.0)
       addressable
-    date (3.3.3)
+    date (3.3.4)
     date_validator (0.9.0)
       activemodel
       activesupport
@@ -490,12 +490,12 @@ GEM
     msgpack (1.7.2)
     multi_xml (0.6.0)
     mustache (1.1.1)
-    net-imap (0.4.4)
+    net-imap (0.4.5)
       date
       net-protocol
     net-pop (0.1.2)
       net-protocol
-    net-protocol (0.2.1)
+    net-protocol (0.2.2)
       timeout
     net-smtp (0.4.0)
       net-protocol
@@ -562,7 +562,7 @@ GEM
     public_suffix (5.0.3)
     puma (5.6.7)
       nio4r (~> 2.0)
-    racc (1.7.2)
+    racc (1.7.3)
     rack (2.2.8)
     rack-attack (6.7.0)
       rack (>= 1.0, < 4)
@@ -731,7 +731,7 @@ GEM
     thor (1.3.0)
     thread_safe (0.3.6)
     tilt (2.3.0)
-    timeout (0.4.0)
+    timeout (0.4.1)
     tomlrb (2.0.3)
     tzinfo (1.2.11)
       thread_safe (~> 0.1)
@@ -808,4 +808,4 @@ RUBY VERSION
    ruby 2.7.7p221
 
 BUNDLED WITH
-   2.4.21
+   2.3.20